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Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.

Protons and neutrons have nearly equal mass and size, but protons carry a positive electrical charge, while neutrons carry no charge at all. Protons and neutrons are bound together by the strong nuclear force, one of the four basic forces in the universe. Protons and neutrons give atoms some of their most basic properties. Elements are defined by two numbers: their atomic number, which is equal to the number of protons they have, and their atomic weight, which is equal to total number of their neutrons and protons. In most lighter atoms, the number of neutrons and protons is equal, and the element is stable. In heavier atoms, however, there are more neutrons than protons, and the element is unstable, eventually losing neutrons through radioactive decay until a neutral state is reached.

Electrons are negatively charged particles. They are bound to their atoms through electromagnetic attraction. Opposite electrical charges attract one another, so the positive charge of the proton helps to keep the negatively charged electron in orbit around the nucleus of the atom. Electrons are different from neutrons in that they cannot be broken down into smaller particles. They are also far smaller and lighter than neutrons and protons. An electron is about one thousandth of the diameter of a proton and an even smaller fraction of its mass. Electrons circle the protons and neutrons at the center of the atom in orbits. These orbits are often called electron shells. The closer the orbit is to the center of the atom, the lower its energy is. There are seven electron shells, and each higher level can hold more electrons than the previous shell. Electrons naturally seek to occupy the lowest shell possible. So, if there is space in a lower shell, an electron will drop down to occupy that space. At temperatures higher than a few hundred degrees, electrons will gain energy and move to a higher shell, but only momentarily. When the electrons drop back down to their natural shell, they emit light. This is why fires and other very hot objects seem to glow.

Electrons are also primarily responsible for many of the chemical properties of atoms. Since electrons seek to occupy the lowest electron shell possible, they will move from one atom to another if there is a space available in a lower electron shell. For example, if there is an atom with an open space in its third shell, and it comes into contact with an atom with electrons in its fourth shell, the first atom will take one of these electrons to complete its third shell. When this happens, the two atoms will be chemically bonded to form a molecule. Furthermore, atoms sometimes lose electrons in collisions with other atoms. When this happens, the radio of protons and electrons in the atom changes, and therefore, the overall electrical charge of the atom changes as well. These atoms are called isotopes, and they have significantly different chemical properties from their parent atoms

According to the passage, all of the following are true of electrons EXCEPT __________. 

A. they are elementary particles and cannot be broken down 

B. they are considerably smaller than neutrons or protons

C. their energy levels are fixed and unchanging 

D. they are kept in orbit by electromagnetic attraction

1
27 tháng 1 2018

Chọn C

Kiến thức: Đọc hiểu

Giải thích:

Theo đoạn văn, tất cả những điều sau đây đều đúng với các electron NGOẠI TRỪ __________.

  A. chúng là các hạt cơ bản và không thể bị phá vỡ

  B. chúng nhỏ hơn đáng kể so với nơtron hoặc proton

  C. mức năng lượng của chúng là cố định và không thay đổi

  D. chúng được giữ trong quỹ đạo bởi lực hút điện từ

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions. Atomic were once thought to be fundamental pieces of matter, but they are in turn made of smaller subatomic particles There are three major subatomic particles neutrons, protons, and electronic. Protons and neutrons can be broken into even smaller units, but these smaller units not occur naturally in nature and are thought to only be produced in...
Đọc tiếp

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.

Atomic were once thought to be fundamental pieces of matter, but they are in turn made of smaller subatomic particles There are three major subatomic particles neutrons, protons, and electronic. Protons and neutrons can be broken into even smaller units, but these smaller units not occur naturally in nature and are thought to only be produced in manmade particle accelerators and perhaps in extreme stellar events like supernovas. The structure of an atom can best be described as a small solar system, with the neutrons at the center and the electrons circling them in various orbits, just as the planets circle the sun. In reality, the structure of an atom is far more complex, because the laws of physics are fundamentally different at the atomic level than at the level of the observable word. The true nature of atomic structure can only be expressed accurately through complex mathematical formulas. This explanation, however, is of little use to most average people.

Protons and neutrons have nearly equal mass and size, but protons carry a positive electrical charge, while neutrons carry no charge at all. Protons and neutrons are bound together by the strong nuclear force, one of the four basic forces in the universe. Protons and neutrons give atoms some of their most basic properties. Elements are defined by two numbers: their atomic number, which is equal to the number of protons they have, and their atomic weight, which is equal to total number of their neutrons and protons. In most lighter atoms, the number of neutrons and protons is equal, and the element is stable. In heavier atoms, however, there are more neutrons than protons, and the element is unstable, eventually losing neutrons through radioactive decay until a neutral state is reached.

According to paragraph 2, an atom's atomic number is determined by __________. 

A. the sum of its protons and electrons 

B. the difference in the mass of its neutrons and protons 

C. the strength of the bond between its protons and neutrons 

D. the total number of protons it has 

1
9 tháng 8 2018

Chọn D

Kiến thức: Đọc hiểu

Giải thích:

Theo đoạn 2, số lượng nguyên tử của một nguyên tố được xác định bởi __________.

  A. tổng số proton và electron của nó

  B. sự khác biệt về khối lượng giữa nơtron và proton của nó

  C. sức mạnh của liên kết giữa các proton và nơtron của nó

  D. tổng số proton nó có

Thông tin: Elements are defined by two numbers: their atomic number, which is equal to the number of protons they have, and their atomic weight, which is equal to total number of their neutrons and protons.

Tạm dịch: Các nguyên tố được xác định bởi hai con số: số lượng nguyên tử, bằng số lượng proton mà chúng có và trọng lượng nguyên tử, bằng tổng số nơtron và proton.

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions. Atomic were once thought to be fundamental pieces of matter, but they are in turn made of smaller subatomic particles There are three major subatomic particles neutrons, protons, and electronic. Protons and neutrons can be broken into even smaller units, but these smaller units not occur naturally in nature and are thought to only be produced in...
Đọc tiếp

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.

Atomic were once thought to be fundamental pieces of matter, but they are in turn made of smaller subatomic particles There are three major subatomic particles neutrons, protons, and electronic. Protons and neutrons can be broken into even smaller units, but these smaller units not occur naturally in nature and are thought to only be produced in manmade particle accelerators and perhaps in extreme stellar events like supernovas. The structure of an atom can best be described as a small solar system, with the neutrons at the center and the electrons circling them in various orbits, just as the planets circle the sun. In reality, the structure of an atom is far more complex, because the laws of physics are fundamentally different at the atomic level than at the level of the observable word. The true nature of atomic structure can only be expressed accurately through complex mathematical formulas. This explanation, however, is of little use to most average people.

Protons and neutrons have nearly equal mass and size, but protons carry a positive electrical charge, while neutrons carry no charge at all. Protons and neutrons are bound together by the strong nuclear force, one of the four basic forces in the universe. Protons and neutrons give atoms some of their most basic properties. Elements are defined by two numbers: their atomic number, which is equal to the number of protons they have, and their atomic weight, which is equal to total number of their neutrons and protons. In most lighter atoms, the number of neutrons and protons is equal, and the element is stable. In heavier atoms, however, there are more neutrons than protons, and the element is unstable, eventually losing neutrons through radioactive decay until a neutral state is reached

The word "stable" in bold in paragraph 2 is closest in meaning to _____. 

A. neutral 

B. unchanging 

C. equal 

D. heavy 

1
12 tháng 1 2017

Chọn B

Kiến thức: Đọc hiểu

Giải thích:

Từ "stable" được in đậm trong đoạn 2 có nghĩa gần nhất với _____.

  A. trung tính            

  B. không thay đổi    

C. bằng                      

D. nặng

Thông tin: In most lighter atoms, the number of neutrons and protons is equal, and the element is stable.

Tạm dịch: Trong hầu hết các nguyên tử nhẹ hơn, số lượng nơtron và proton bằng nhau và nguyên tố này bền vững

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions. Atomic were once thought to be fundamental pieces of matter, but they are in turn made of smaller subatomic particles There are three major subatomic particles neutrons, protons, and electronic. Protons and neutrons can be broken into even smaller units, but these smaller units not occur naturally in nature and are thought to only be produced in...
Đọc tiếp

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.

Atomic were once thought to be fundamental pieces of matter, but they are in turn made of smaller subatomic particles There are three major subatomic particles neutrons, protons, and electronic. Protons and neutrons can be broken into even smaller units, but these smaller units not occur naturally in nature and are thought to only be produced in manmade particle accelerators and perhaps in extreme stellar events like supernovas. The structure of an atom can best be described as a small solar system, with the neutrons at the center and the electrons circling them in various orbits, just as the planets circle the sun. In reality, the structure of an atom is far more complex, because the laws of physics are fundamentally different at the atomic level than at the level of the observable word. The true nature of atomic structure can only be expressed accurately through complex mathematical formulas. This explanation, however, is of little use to most average people.

Protons and neutrons have nearly equal mass and size, but protons carry a positive electrical charge, while neutrons carry no charge at all. Protons and neutrons are bound together by the strong nuclear force, one of the four basic forces in the universe. Protons and neutrons give atoms some of their most basic properties. Elements are defined by two numbers: their atomic number, which is equal to the number of protons they have, and their atomic weight, which is equal to total number of their neutrons and protons. In most lighter atoms, the number of neutrons and protons is equal, and the element is stable. In heavier atoms, however, there are more neutrons than protons, and the element is unstable, eventually losing neutrons through radioactive decay until a neutral state is reached.

 

In paragraph 1, why does the author compare the structure of an atom to a solar system?

A. To provide an explanation of atomic structure that will be easily understood

B. To show the influence of atomic structure on the world at the observable level

C. To show that the complex mathematical formulas used to explain atomic structure are inaccurate

D. To contrast the size of atoms with the size of objects at the observable level

1
21 tháng 4 2018

Chọn A

Kiến thức: Đọc hiểu

Giải thích:  

Trong đoạn 1, tại sao tác giả lại so sánh cấu trúc của một nguyên tử với hệ Mặt Trời?

  A. Để đưa ra một lời giải thích về cấu trúc nguyên tử một cách dễ hiểu.

  B. Để chỉ ra ảnh hưởng của cấu trúc nguyên tử đến thế giới ở cấp độ quan sát được.

  C. Để chỉ ra rằng các công thức toán học phức tạp được sử dụng để giải thích cấu trúc nguyên tử là không chính xác.

  D. Để tương phản kích thước của các nguyên tử với kích thước của các vật thể ở mức có thể quan sát được.

Thông tin: The structure of an atom can best be described as a small solar system, with the neutrons at the center and the electrons circling them in various orbits, just as the planets circle the sun.

Tạm dịch: Cấu trúc của một nguyên tử có thể được mô tả chính xác nhất giống như một hệ mặt trời nhỏ, với các nơtron ở trung tâm và các electron quay quanh chúng theo các quỹ đạo khác nhau, giống như các hành tinh quay quanh Mặt Trời

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questionsAtomic were once thought to be fundamental pieces of matter, but they are in turn made of smaller subatomic particles There are three major subatomic particles neutrons, protons, and electronic. Protons and neutrons can be broken into even smaller units, but these smaller units not occur naturally in nature and are thought to only be produced in...
Đọc tiếp

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions

Atomic were once thought to be fundamental pieces of matter, but they are in turn made of smaller subatomic particles There are three major subatomic particles neutrons, protons, and electronic. Protons and neutrons can be broken into even smaller units, but these smaller units not occur naturally in nature and are thought to only be produced in manmade particle accelerators and perhaps in extreme stellar events like supernovas. The structure of an atom can best be described as a small solar system, with the neutrons at the center and the electrons circling them in various orbits, just as the planets circle the sun. In reality, the structure of an atom is far more complex, because the laws of physics are fundamentally different at the atomic level than at the level of the observable word. The true nature of atomic structure can only be expressed accurately through complex mathematical formulas. This explanation, however, is of little use to most average people.

Protons and neutrons have nearly equal mass and size, but protons carry a positive electrical charge, while neutrons carry no charge at all. Protons and neutrons are bound together by the strong nuclear force, one of the four basic forces in the universe. Protons and neutrons give atoms some of their most basic properties. Elements are defined by two numbers: their atomic number, which is equal to the number of protons they have, and their atomic weight, which is equal to total number of their neutrons and protons. In most lighter atoms, the number of neutrons and protons is equal, and the element is stable. In heavier atoms, however, there are more neutrons than protons, and the element is unstable, eventually losing neutrons through radioactive decay until a neutral state is reached.

Electrons are negatively charged particles. They are bound to their atoms through electromagnetic attraction. Opposite electrical charges attract one another, so the positive charge of the proton helps to keep the negatively charged electron in orbit around the nucleus of the atom. Electrons are different from neutrons in that they cannot be broken down into smaller particles. They are also far smaller and lighter than neutrons and protons. An electron is about one thousandth of the diameter of a proton and an even smaller fraction of its mass. Electrons circle the protons and neutrons at the center of the atom in orbits. These orbits are often called electron shells. The closer the orbit is to the center of the atom, the lower its energy is. There are seven electron shells, and each higher level can hold more electrons than the previous shell. Electrons naturally seek to occupy the lowest shell possible. So, if there is space in a lower shell, an electron will drop down to occupy that space. At temperatures higher than a few hundred degrees, electrons will gain energy and move to a higher shell, but only momentarily. When the electrons drop back down to their natural shell, they emit light. This is why fires and other very hot objects seem to glow

According to the information in paragraph 2, what will happen if an atom has more neutrons than protons? 

A. It will not have enough of a positive electrical charge to keep its electrons in orbit

B. Its extra neutrons will be converted into light energy

C. It will slowly give off neutrons until the atom becomes stable

D. Its nucleus will explode in a supernova

1
2 tháng 12 2018

Chọn C

Kiến thức: Đọc hiểu

Giải thích: 20

Theo thông tin trong đoạn 2, điều gì sẽ xảy ra nếu một nguyên tử có nhiều nơtron hơn proton?

  A. Nó sẽ không có đủ điện tích dương để giữ các electron của nó trong quỹ đạo.

  B. Các nơtron thừa ra của nó sẽ được chuyển thành năng lượng ánh sáng.

  C. Nó sẽ từ từ giải phóng nơtron cho đến khi nguyên tử trở về dạng bền vững.

  D. Hạt nhân của nó sẽ phát nổ trong một sao băng.

Thông tin: In heavier atoms, however, there are more neutrons than protons, and the element is unstable, eventually losing neutrons through radioactive decay until a neutral state is reached.

Tạm dịch: Tuy nhiên, trong các nguyên tử nặng hơn, có nhiều nơtron hơn proton và nguyên tố này không bền vững, cuối cùng mất đi nơtron thông qua sự phân rã phóng xạ cho đến khi đạt được trạng thái cân bằng

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questionsProtons and neutrons have nearly equal mass and size, but protons carry a positive electrical charge, while neutrons carry no charge at all. Protons and neutrons are bound together by the strong nuclear force, one of the four basic forces in the universe. Protons and neutrons give atoms some of their most basic properties. Elements are defined by two...
Đọc tiếp

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions

Protons and neutrons have nearly equal mass and size, but protons carry a positive electrical charge, while neutrons carry no charge at all. Protons and neutrons are bound together by the strong nuclear force, one of the four basic forces in the universe. Protons and neutrons give atoms some of their most basic properties. Elements are defined by two numbers: their atomic number, which is equal to the number of protons they have, and their atomic weight, which is equal to total number of their neutrons and protons. In most lighter atoms, the number of neutrons and protons is equal, and the element is stable. In heavier atoms, however, there are more neutrons than protons, and the element is unstable, eventually losing neutrons through radioactive decay until a neutral state is reached.

Electrons are negatively charged particles. They are bound to their atoms through electromagnetic attraction. Opposite electrical charges attract one another, so the positive charge of the proton helps to keep the negatively charged electron in orbit around the nucleus of the atom. Electrons are different from neutrons in that they cannot be broken down into smaller particles. They are also far smaller and lighter than neutrons and protons. An electron is about one thousandth of the diameter of a proton and an even smaller fraction of its mass. Electrons circle the protons and neutrons at the center of the atom in orbits. These orbits are often called electron shells. The closer the orbit is to the center of the atom, the lower its energy is. There are seven electron shells, and each higher level can hold more electrons than the previous shell. Electrons naturally seek to occupy the lowest shell possible. So, if there is space in a lower shell, an electron will drop down to occupy that space. At temperatures higher than a few hundred degrees, electrons will gain energy and move to a higher shell, but only momentarily. When the electrons drop back down to their natural shell, they emit light. This is why fires and other very hot objects seem to glow.

Electrons are also primarily responsible for many of the chemical properties of atoms. Since electrons seek to occupy the lowest electron shell possible, they will move from one atom to another if there is a space available in a lower electron shell. For example, if there is an atom with an open space in its third shell, and it comes into contact with an atom with electrons in its fourth shell, the first atom will take one of these electrons to complete its third shell. When this happens, the two atoms will be chemically bonded to form a molecule. Furthermore, atoms sometimes lose electrons in collisions with other atoms. When this happens, the radio of protons and electrons in the atom changes, and therefore, the overall electrical charge of the atom changes as well. These atoms are called isotopes, and they have significantly different chemical properties from their parent atoms

According to paragraph 4, which property of electrons is responsible for chemical bonding? 

A. Their electromagnetic attraction to protons

B. Their tendency to occupy the lowest possible electron shell 

C. The fact that they cannot be broken into smaller particles 

D. Their ability to break free of their atom during a collision

1
21 tháng 12 2017

Chọn B

Kiến thức: Đọc hiểu

Giải thích:

Theo đoạn 4, tính chất nào của electron đóng vai trò hình thành nên liên kết hóa học?

  A. Sức hút điện từ của chúng đối với các proton

  B. Xu hướng chiếm lớp electron thấp nhất có thể

  C. Thực tế là chúng không thể bị vỡ thành các hạt nhỏ hơn

  D. Khả năng thoát khỏi nguyên tử của chúng khi va chạm

Thông tin: Since electrons seek to occupy the lowest electron shell possible, they will move from one atom to another if there is a space available in a lower electron shell. For example, if there is an atom with an open space in its third shell, and it comes into contact with an atom with electrons in its fourth shell, the first atom will take one of these electrons to complete its third shell. When this happens, the two atoms will be chemically bonded to form a molecule.

Tạm dịch: Vì các electron tìm cách chiếm lớp electron thấp nhất có thể, chúng sẽ di chuyển từ nguyên tử này sang nguyên tử khác nếu có một khoảng trống có sẵn trong lớp electron thấp hơn. Ví dụ, nếu có một nguyên tử có không gian mở ở lớp vỏ thứ ba và nó tiếp xúc với một nguyên tử có electron ở lớp vỏ thứ tư, thì nguyên tử đầu tiên sẽ lấy một trong những electron này để hoàn thành lớp vỏ thứ ba của nó. Khi điều này xảy ra, hai nguyên tử sẽ được liên kết hóa học để tạo thành một phân tử.

Dịch bài đọc:

Nguyên tử từng được cho là những hạt cơ bản của vật chất, nhưng chúng lần lượt được cấu thành từ các hạt nhỏ hơn bên trong nguyên tử. Có ba hạt bên trong nguyên tử chính là nơtron, proton và electron. Proton và nơtron có thể bị phá vỡ thành các đơn vị nhỏ hơn, nhưng những đơn vị nhỏ hơn này không tự có trong tự nhiên và được cho là chỉ được tạo ra trong các máy gia tốc hạt nhân tạo và có lẽ trong các sự kiện liên quan đến sao như sao băng. Cấu trúc của một nguyên tử có thể được mô tả chính xác nhất giống như một hệ mặt trời nhỏ, với các nơtron ở trung tâm và các electron quay quanh chúng theo các quỹ đạo khác nhau, giống như các hành tinh quay quanh Mặt Trời. Trong thực tế, cấu trúc của một nguyên tử phức tạp hơn nhiều, bởi vì các định luật vật lý khác nhau về cơ bản ở cấp độ nguyên tử so với những từ ngữ có thể nhận thấy được. Bản chất thực sự của cấu trúc nguyên tử chỉ có thể được thể hiện chính xác thông qua các công thức toán học phức tạp. Tuy nhiên, lời giải thích này ít được sử dụng với hầu hết những người bình thường.

Proton và nơtron có khối lượng và kích thước gần bằng nhau, nhưng proton mang điện tích dương, trong khi nơtron không mang điện tích nào cả. Proton và nơtron liên kết với nhau bằng lực hạt nhân mạnh, một trong bốn lực cơ bản trong vũ trụ. Proton và nơtron tạo nên một số tính chất cơ bản nhất của nguyên tử. Các nguyên tố được xác định bởi hai con số: số lượng nguyên tử, bằng số lượng proton mà chúng có và trọng lượng nguyên tử, bằng tổng số nơtron và proton. Trong hầu hết các nguyên tử nhẹ hơn, số lượng nơtron và proton bằng nhau và nguyên tố này bền vững. Tuy nhiên, trong các nguyên tử nặng hơn, có nhiều nơtron hơn proton và nguyên tố này không bền vững, cuối cùng mất đi nơtron thông qua sự phân rã phóng xạ cho đến khi đạt được trạng thái cân bằng.

Electron là các hạt tích điện âm. Chúng gắn chặt với nguyên tử thông qua lực hút điện từ. Các điện tích trái dấu nhau thì hút nhau, vì vậy điện tích dương của proton giữ electron tích điện âm trong quỹ đạo quay xung quanh hạt nhân của nguyên tử. Electron khác với nơtron ở chỗ chúng không thể bị phân hủy thành các hạt nhỏ hơn. Chúng cũng nhỏ và nhẹ hơn nhiều so với nơtron và proton. Một electron có đường kính bằng một phần nghìn đường kính của một proton và bằng một phần nhỏ hơn nữa khối lượng của proton. Các electron quay tròn quanh các proton và nơtron ở nhân của nguyên tử theo các quỹ đạo. Những quỹ đạo này thường được gọi là lớp electron. Quỹ đạo càng gần nhân của nguyên tử thì năng lượng của nó càng thấp. Có bảy lớp electron và mỗi lớp cao hơn có thể chứa nhiều electron hơn lớp trước. Electron có cơ chế tự tìm và chiếm lớp thấp nhất có thể. Vì vậy, nếu còn không gian trong lớp electron thấp hơn, một electron sẽ rơi xuống để chiếm không gian đó. Ở nhiệt độ cao hơn vài trăm độ, các electron sẽ thu được năng lượng và di chuyển đến lớp electron cao hơn, nhưng chỉ trong giây lát. Khi các electron rơi trở lại lớp ban đầu của mình, chúng phát ra ánh sáng. Đây là lý do tại sao lửa và các vật thể rất nóng khác phát sáng.

Electron cũng đóng vai trò chính trong việc hình thành nhiều tính chất hóa học của các nguyên tử. Vì các electron tìm cách chiếm lớp electron thấp nhất có thể, chúng sẽ di chuyển từ nguyên tử này sang nguyên tử khác nếu có một khoảng trống có sẵn trong lớp electron thấp hơn. Ví dụ, nếu có một nguyên tử có không gian mở ở lớp vỏ thứ ba và nó tiếp xúc với một nguyên tử có electron ở lớp vỏ thứ tư, thì nguyên tử đầu tiên sẽ lấy một trong những electron này để hoàn thành lớp vỏ thứ ba của nó. Khi điều này xảy ra, hai nguyên tử sẽ được liên kết hóa học để tạo thành một phân tử. Hơn nữa, các nguyên tử đôi khi mất electron khi va chạm với các nguyên tử khác. Khi điều này xảy ra, phóng xạ của proton và electron trong nguyên tử thay đổi, và do đó, tổng điện tích của nguyên tử cũng thay đổi. Những nguyên tử này được gọi là đồng vị và chúng có tính chất hóa học khác biệt đáng kể so với nguyên tử mẹ của chúng

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions. Atomic were once thought to be fundamental pieces of matter, but they are in turn made of smaller subatomic particles There are three major subatomic particles neutrons, protons, and electronic. Protons and neutrons can be broken into even smaller units, but these smaller units not occur naturally in nature and are thought to only be produced in...
Đọc tiếp

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.

Atomic were once thought to be fundamental pieces of matter, but they are in turn made of smaller subatomic particles There are three major subatomic particles neutrons, protons, and electronic. Protons and neutrons can be broken into even smaller units, but these smaller units not occur naturally in nature and are thought to only be produced in manmade particle accelerators and perhaps in extreme stellar events like supernovas. The structure of an atom can best be described as a small solar system, with the neutrons at the center and the electrons circling them in various orbits, just as the planets circle the sun. In reality, the structure of an atom is far more complex, because the laws of physics are fundamentally different at the atomic level than at the level of the observable word. The true nature of atomic structure can only be expressed accurately through complex mathematical formulas. This explanation, however, is of little use to most average people.

Protons and neutrons have nearly equal mass and size, but protons carry a positive electrical charge, while neutrons carry no charge at all. Protons and neutrons are bound together by the strong nuclear force, one of the four basic forces in the universe. Protons and neutrons give atoms some of their most basic properties. Elements are defined by two numbers: their atomic number, which is equal to the number of protons they have, and their atomic weight, which is equal to total number of their neutrons and protons. In most lighter atoms, the number of neutrons and protons is equal, and the element is stable. In heavier atoms, however, there are more neutrons than protons, and the element is unstable, eventually losing neutrons through radioactive decay until a neutral state is reached.

Electrons are negatively charged particles. They are bound to their atoms through electromagnetic attraction. Opposite electrical charges attract one another, so the positive charge of the proton helps to keep the negatively charged electron in orbit around the nucleus of the atom. Electrons are different from neutrons in that they cannot be broken down into smaller particles. They are also far smaller and lighter than neutrons and protons. An electron is about one thousandth of the diameter of a proton and an even smaller fraction of its mass. Electrons circle the protons and neutrons at the center of the atom in orbits. These orbits are often called electron shells. The closer the orbit is to the center of the atom, the lower its energy is. There are seven electron shells, and each higher level can hold more electrons than the previous shell. Electrons naturally seek to occupy the lowest shell possible. So, if there is space in a lower shell, an electron will drop down to occupy that space. At temperatures higher than a few hundred degrees, electrons will gain energy and move to a higher shell, but only momentarily. When the electrons drop back down to their natural shell, they emit light. This is why fires and other very hot objects seem to glow.

The phrase "one another" in bold in paragraph 3 refers to _______. 

A. electrons 

B. electrical charges 

C. particles 

D. atoms 

1
26 tháng 9 2018

Chọn B

Kiến thức: Đọc hiểu

Giải thích:

Cụm từ "one another" in đậm trong đoạn 3 đề cập đến _______.

  A. electron               

B. các điện tích           

C. các hạt                   

D. các nguyên tử

Thông tin: Opposite electrical charges attract one another, so the positive charge of the proton helps to keep the negatively charged electron in orbit around the nucleus of the atom.

Tạm dịch: Các điện tích trái dấu nhau thì hút nhau, vì vậy điện tích dương của proton giữ electron tích điện âm trong quỹ đạo quay xung quanh hạt nhân của nguyên tử

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.Atomic were once thought to be fundamental pieces of matter, but they are in turn made of smaller subatomic particles There are three major subatomic particles neutrons, protons, and electronic. Protons and neutrons can be broken into even smaller units, but these smaller units not occur naturally in nature and are thought to only be produced in...
Đọc tiếp

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.

Atomic were once thought to be fundamental pieces of matter, but they are in turn made of smaller subatomic particles There are three major subatomic particles neutrons, protons, and electronic. Protons and neutrons can be broken into even smaller units, but these smaller units not occur naturally in nature and are thought to only be produced in manmade particle accelerators and perhaps in extreme stellar events like supernovas. The structure of an atom can best be described as a small solar system, with the neutrons at the center and the electrons circling them in various orbits, just as the planets circle the sun. In reality, the structure of an atom is far more complex, because the laws of physics are fundamentally different at the atomic level than at the level of the observable word. The true nature of atomic structure can only be expressed accurately through complex mathematical formulas. This explanation, however, is of little use to most average people.

Protons and neutrons have nearly equal mass and size, but protons carry a positive electrical charge, while neutrons carry no charge at all. Protons and neutrons are bound together by the strong nuclear force, one of the four basic forces in the universe. Protons and neutrons give atoms some of their most basic properties. Elements are defined by two numbers: their atomic number, which is equal to the number of protons they have, and their atomic weight, which is equal to total number of their neutrons and protons. In most lighter atoms, the number of neutrons and protons is equal, and the element is stable. In heavier atoms, however, there are more neutrons than protons, and the element is unstable, eventually losing neutrons through radioactive decay until a neutral state is reached.

Electrons are negatively charged particles. They are bound to their atoms through electromagnetic attraction. Opposite electrical charges attract one another, so the positive charge of the proton helps to keep the negatively charged electron in orbit around the nucleus of the atom. Electrons are different from neutrons in that they cannot be broken down into smaller particles. They are also far smaller and lighter than neutrons and protons. An electron is about one thousandth of the diameter of a proton and an even smaller fraction of its mass. Electrons circle the protons and neutrons at the center of the atom in orbits. These orbits are often called electron shells. The closer the orbit is to the center of the atom, the lower its energy is. There are seven electron shells, and each higher level can hold more electrons than the previous shell. Electrons naturally seek to occupy the lowest shell possible. So, if there is space in a lower shell, an electron will drop down to occupy that space. At temperatures higher than a few hundred degrees, electrons will gain energy and move to a higher shell, but only momentarily. When the electrons drop back down to their natural shell, they emit light. This is why fires and other very hot objects seem to glow.

According to paragraph 3, when does an atom produce light?

A. When it has more electrons than its electron shells can hold

B. When energy is added to the outermost electron shell

C. When an electron drops back to its original electron shell

D. When an electron is transferred from one atom to another

1
10 tháng 4 2019

Chọn C

Kiến thức: Đọc hiểu

Giải thích:

Theo đoạn 3, khi nào một nguyên tử phát ra ánh sáng?

  A. Khi nó có nhiều electron hơn so với số lượng mà lớp electron của nó có thể giữ được.

  B. Khi năng lượng được thu thêm vào lớp electron ngoài cùng.

  C. Khi một electron rơi trở lại lớp electron ban đầu của nó.

  D. Khi một electron được chuyển từ nguyên tử này sang nguyên tử khác.

Thông tin: When the electrons drop back down to their natural shell, they emit light.

Tạm dịch: Khi các electron rơi trở lại lớp ban đầu của mình, chúng phát ra ánh sáng

Read the following passage, and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions.Atomic were once thought to be fundamental pieces of matter, but they are in turn made of smaller subatomic particles. There are three major subatomic particles neutrons, protons, and electronic. Protons and neutrons can be broken into even smaller units, but these smaller units do not occur naturally in nature and are thought to only be produced in manmade...
Đọc tiếp

Read the following passage, and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions.

Atomic were once thought to be fundamental pieces of matter, but they are in turn made of smaller subatomic particles. There are three major subatomic particles neutrons, protons, and electronic. Protons and neutrons can be broken into even smaller units, but these smaller units do not occur naturally in nature and are thought to only be produced in manmade particle accelerators and perhaps in extreme stellar events like supernovas. The structure of an atom can best be described as a small solar system, with the neutrons at the center and the electrons circling them in various orbits, just as the planets circle the sun .In reality, the structure of an atom is far more complex, because the laws of physics are fundamentally different at the atomic level than of the level of the observable word. The true nature of atomic structure can only be expressed accurately through complex mathematical formulas .This explanation, however, is of little use to most average people.

Protons and neutrons have nearly equal mass and size, but protons carry a positive electrical charge, while neutrons carry no charge at all. Protons and neutrons are bound together by the strong nuclear force, one of the four basic forces in the universe. Protons and neutrons give atoms some of their most basic properties. Elements are defined by two numbers; their atomic number , which is equal to the number of protons they have, and their atomic weight , which is equal to total number of their neutrons and protons. In most lighter atoms , the number of neutrons and protons is equal , and the element is stable. In heavier atoms, however, there are more neutrons than protons , and the element is unstable, eventually losing neutrons through radioactive decay until a neutral state is reached.

Electrons are negatively charged particles. They are bound to their atoms through electromagnetic attraction. Opposite electrical charges attract one another, so the positive charge of the proton helps keep the negatively charged electron in orbit around the nucleus of the atom. Electrons are different from neutrons in that they cannot be broken down into smaller particles. They are also far smaller and lighter than neutrons and protons. An electron is about one thousandth of the diameter of a proton and an even smaller fraction of its mass. Electrons circle the protons and neutrons at the center of the atom in orbit. These orbits are often called electron shells. The closer the orbit is to the center of the atom, the lower its energy is. There are seven electron shells, and each higher level can hold more electron than the previous shell. Electrons naturally seek to occupy the lowest shell possible .So if there is space in a lower shell, an electron will drop down to occupy that space. At temperatures higher than a few hundred degrees, electrons will gain energy and move to a higher shell, but only momentarily. When the electrons drop back down to their natural shell, they emit light .This is why fires and other very hot objects seem to glow.

Electrons are also primarily responsible for many of the chemical properties of atoms. Since electrons seek to occupy the lowest electron shell possible, they will move from one atom to another if there is a space available in a lower electron shell. For example, if there is an atom with an open space in its third shell, and it comes into contact with an atom with electrons in its fourth shell, the first atom will take one of these electrons to complete its third shell. When this happens, the two atoms will be chemically bonded to form a molecule. Furthermore, atoms sometimes lose electrons in collisions with other atoms. When it happens, the radio of protons and electrons in the atom changes, and therefore, the overall electrical charge of the atom changes as well. These atoms are called isotopes, and they have significantly different chemical properties from their parent atoms.

According to the information in paragraph 2, what will happen if an atom has more neutrons than protons?

A. It will not have enough of a positive electrical charge to keep its electrons in orbit

B. Its nucleus will explode in a supernova

C. It will slowly give off neutrons until the atom becomes stable

D. Its extra neutrons will be converted into light energy

1
20 tháng 12 2018

Đáp án là C

Theo thông tin ở đoạn 2, điều gì sẽ xảy ra nếu 1 nguyên tử có nhiều notron hơn proton?

A. Nó sẽ không có đủ điện cực dương để giữ các electron theo đúng quỹ đạo.

B. Hạt nhân của nó sẽ nổ ở dạng một siêu tân binh.

C. Nó sẽ mất dần notron cho đến khi nguyên tử trở nên cân bằng.

D. Những notron thừa sẽ bị chuyển đổi thành năng lượng ánh sáng.

Dẫn chứng: In heavier atoms, however, there are more neutrons than protons , and the element is unstable, eventually losing neutrons through radioactive decay until a neutral state is reacheD

Read the following passage, and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions.Atomic were once thought to be fundamental pieces of matter, but they are in turn made of smaller subatomic particles. There are three major subatomic particles neutrons, protons, and electronic. Protons and neutrons can be broken into even smaller units, but these smaller units do not occur naturally in nature and are thought to only be produced in manmade...
Đọc tiếp

Read the following passage, and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions.

Atomic were once thought to be fundamental pieces of matter, but they are in turn made of smaller subatomic particles. There are three major subatomic particles neutrons, protons, and electronic. Protons and neutrons can be broken into even smaller units, but these smaller units do not occur naturally in nature and are thought to only be produced in manmade particle accelerators and perhaps in extreme stellar events like supernovas. The structure of an atom can best be described as a small solar system, with the neutrons at the center and the electrons circling them in various orbits, just as the planets circle the sun .In reality, the structure of an atom is far more complex, because the laws of physics are fundamentally different at the atomic level than of the level of the observable word. The true nature of atomic structure can only be expressed accurately through complex mathematical formulas .This explanation, however, is of little use to most average people.

Protons and neutrons have nearly equal mass and size, but protons carry a positive electrical charge, while neutrons carry no charge at all. Protons and neutrons are bound together by the strong nuclear force, one of the four basic forces in the universe. Protons and neutrons give atoms some of their most basic properties. Elements are defined by two numbers; their atomic number , which is equal to the number of protons they have, and their atomic weight , which is equal to total number of their neutrons and protons. In most lighter atoms , the number of neutrons and protons is equal , and the element is stable. In heavier atoms, however, there are more neutrons than protons , and the element is unstable, eventually losing neutrons through radioactive decay until a neutral state is reached.

Electrons are negatively charged particles. They are bound to their atoms through electromagnetic attraction. Opposite electrical charges attract one another, so the positive charge of the proton helps keep the negatively charged electron in orbit around the nucleus of the atom. Electrons are different from neutrons in that they cannot be broken down into smaller particles. They are also far smaller and lighter than neutrons and protons. An electron is about one thousandth of the diameter of a proton and an even smaller fraction of its mass. Electrons circle the protons and neutrons at the center of the atom in orbit. These orbits are often called electron shells. The closer the orbit is to the center of the atom, the lower its energy is. There are seven electron shells, and each higher level can hold more electron than the previous shell. Electrons naturally seek to occupy the lowest shell possible .So if there is space in a lower shell, an electron will drop down to occupy that space. At temperatures higher than a few hundred degrees, electrons will gain energy and move to a higher shell, but only momentarily. When the electrons drop back down to their natural shell, they emit light .This is why fires and other very hot objects seem to glow.

Electrons are also primarily responsible for many of the chemical properties of atoms. Since electrons seek to occupy the lowest electron shell possible, they will move from one atom to another if there is a space available in a lower electron shell. For example, if there is an atom with an open space in its third shell, and it comes into contact with an atom with electrons in its fourth shell, the first atom will take one of these electrons to complete its third shell. When this happens, the two atoms will be chemically bonded to form a molecule. Furthermore, atoms sometimes lose electrons in collisions with other atoms. When it happens, the radio of protons and electrons in the atom changes, and therefore, the overall electrical charge of the atom changes as well. These atoms are called isotopes, and they have significantly different chemical properties from their parent atoms.

According to paragraph 2, an atom’s atomic number is determined by

A. The sum of its protons and electrons

B. The different in the mass of its neutrons and protons

C. The strength of the bond between its protons and neutrons

D. The total number of protons it has

1
23 tháng 4 2017

Đáp án là D

Theo đoạn 2, số nguyên tử của một nguyên tử được xác định bởi

A. Tổng các hạt proton và electron

B. Số lượng notron và proton khác nhau.

C. Sức mạnh kết hợp giữa các hạt proton và notron.

D. Tổng số proton mà nó có.

Dẫn chứng: Elements are defined by two numbers; their atomic number , which is equal to the number of protons they have