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
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
she got the salary last week, she has complained that she is out of money
Since our train leaves at 10.30, it is _______that everyone be at the station no later than 10.15
In this course, students receive _______ in the basic English grammar
Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 33 to 37.
When you first arrive in a foreign culture, often your first reaction is completely positive. Everything seems exciting, different and fascinating. It’s an (33)______. If you are just on a short holiday, you will probably never leave this phase.
(34)_______, if you stay longer, your attitude can start to change. As you start to realize (35)_____ little you really understand the new culture, life can get frustrating. People misunderstand what you are trying to say, or they may laugh at you when you say something incorrectly. Even simple things, like posting a letter, can seem very difficult to you. Thus, you are likely to get angry or upset when things go wrong.
With time, though, you start to (36)______ to become more comfortable with the differences and better able to handle frustrating situations. Your (37)______ of humor reappears. Finally, you may feel enthusiastic about the culture once again, enjoy living in it, and even prefer certain aspects of the culture to your own.
(Adapted from Navigate – Coursebook, OUP 2015)
Điền ô 36
Mark the letter A, B, C or D on your answer sheet to indicate the word(s) CLOSEST in meaning to the underlined word(s) in each of the following questions
Our team must develop a new strategy in order to deal with the serious problem
Choose the item (A, B, C or D) that best completes the unfinished statement.
Sometimes people add to what they say even when they don't talk. Gestures are the "silent language" of every culture. We point a finger or move another part of the body to show what we want to say. It is important to know the body language of every country or we may be misunderstood. In the United States, people greet each other with a handshake in a formal introduction. The handshake must be firm. If the handshake is weak, it is a sign of weakness or unfriendliness. Friends may place a hand on the other's arm or shoulder. Some people, usually women, greet a friend with a hug.
Space is important to Americans. When two people talk to each other, they usually stand about two and a half feet away and at an angle, so they are not facing each other directly. Americans get uncomfortable when a person stands too close. They will move back to have their space. If Americans touch another person by accident, they say, "Pardon me." or "Excuse me." Americans like to look the other person in the eyes when they are talking. If you don't do so, it means you are bored, hiding something, or are not interested. But when you are stare at someone, it is not polite. For Americans, thumbs-up means yes, very good, or well done. Thumbs down means the opposite. To call a waiter, raise one hand to head level or above. To show you want the check, make a movement with your hands as if you are signing a piece of paper. It is all right to point at things but not at people with the hand and index finger. Americans shake their index finger at children when they scold them and pat them on the head when they admire them. Learning a culture's body language is sometimes confusing. If you don't know what to do, the safest thing to do is to smile
If you are introduced to a stranger from the USA, you should _______.
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 from 31 to 35.
Just as you designate and separate your physical workspace, you should be clear about when you’re working and when you’re not. You’ll get your best work done and be most ready to transition back to the office if you stick with your regular hours. Plus, if your role is collaborative, being on the same schedule as your coworkers makes everything much easier.
“The biggest difference between working from home and working in the office is that you are in charge of your environment and have to treat yourself like an employee,” Yurovsky says. This means holding yourself accountable, but also recognizing when enough is enough, just as a good manager might. “If you feel yourself extending your work hours because you are not doing anything in the evening...tell yourself it’s time to put work away, recharge, and start tomorrow with a fresh mind. The work will be there in the morning.”
If you live with other people, this separation is even more critical. Communicate with the people whom you live with to establish boundaries so you can cut down on distractions during the workday—and then disconnect and give the people you care about your full attention. Having a separate time and space to work will allow you to be more present in your home life.
(Adapted from https://www.themuse.com/)
The word “whom” in paragraph 1 refers to ______.
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 from 31 to 35.
Just as you designate and separate your physical workspace, you should be clear about when you’re working and when you’re not. You’ll get your best work done and be most ready to transition back to the office if you stick with your regular hours. Plus, if your role is collaborative, being on the same schedule as your coworkers makes everything much easier.
“The biggest difference between working from home and working in the office is that you are in charge of your environment and have to treat yourself like an employee,” Yurovsky says. This means holding yourself accountable, but also recognizing when enough is enough, just as a good manager might. “If you feel yourself extending your work hours because you are not doing anything in the evening...tell yourself it’s time to put work away, recharge, and start tomorrow with a fresh mind. The work will be there in the morning.”
If you live with other people, this separation is even more critical. Communicate with the people whom you live with to establish boundaries so you can cut down on distractions during the workday—and then disconnect and give the people you care about your full attention. Having a separate time and space to work will allow you to be more present in your home life.
(Adapted from https://www.themuse.com/)
What is the useful advice for those who work from home at night?
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 from 31 to 35.
Just as you designate and separate your physical workspace, you should be clear about when you’re working and when you’re not. You’ll get your best work done and be most ready to transition back to the office if you stick with your regular hours. Plus, if your role is collaborative, being on the same schedule as your coworkers makes everything much easier.
“The biggest difference between working from home and working in the office is that you are in charge of your environment and have to treat yourself like an employee,” Yurovsky says. This means holding yourself accountable, but also recognizing when enough is enough, just as a good manager might. “If you feel yourself extending your work hours because you are not doing anything in the evening...tell yourself it’s time to put work away, recharge, and start tomorrow with a fresh mind. The work will be there in the morning.”
If you live with other people, this separation is even more critical. Communicate with the people whom you live with to establish boundaries so you can cut down on distractions during the workday—and then disconnect and give the people you care about your full attention. Having a separate time and space to work will allow you to be more present in your home life.
(Adapted from https://www.themuse.com/)
According to paragraph 1, if you work on the same schedule as your co-workers, your work may be ______.
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 from 31 to 35.
Just as you designate and separate your physical workspace, you should be clear about when you’re working and when you’re not. You’ll get your best work done and be most ready to transition back to the office if you stick with your regular hours. Plus, if your role is collaborative, being on the same schedule as your coworkers makes everything much easier.
“The biggest difference between working from home and working in the office is that you are in charge of your environment and have to treat yourself like an employee,” Yurovsky says. This means holding yourself accountable, but also recognizing when enough is enough, just as a good manager might. “If you feel yourself extending your work hours because you are not doing anything in the evening...tell yourself it’s time to put work away, recharge, and start tomorrow with a fresh mind. The work will be there in the morning.”
If you live with other people, this separation is even more critical. Communicate with the people whom you live with to establish boundaries so you can cut down on distractions during the workday—and then disconnect and give the people you care about your full attention. Having a separate time and space to work will allow you to be more present in your home life.
(Adapted from https://www.themuse.com/)
The word “accountable” in paragraph 2 is closest in meaning to ______.
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 from 31 to 35.
Just as you designate and separate your physical workspace, you should be clear about when you’re working and when you’re not. You’ll get your best work done and be most ready to transition back to the office if you stick with your regular hours. Plus, if your role is collaborative, being on the same schedule as your coworkers makes everything much easier.
“The biggest difference between working from home and working in the office is that you are in charge of your environment and have to treat yourself like an employee,” Yurovsky says. This means holding yourself accountable, but also recognizing when enough is enough, just as a good manager might. “If you feel yourself extending your work hours because you are not doing anything in the evening...tell yourself it’s time to put work away, recharge, and start tomorrow with a fresh mind. The work will be there in the morning.”
If you live with other people, this separation is even more critical. Communicate with the people whom you live with to establish boundaries so you can cut down on distractions during the workday—and then disconnect and give the people you care about your full attention. Having a separate time and space to work will allow you to be more present in your home life.
(Adapted from https://www.themuse.com/)
Which best serves as the title for the passage?
Read the following passage and mark the letter A, B, C, or D to indicate the correct word or phrase that best fits each of the numbered blanks.
Sir Isaac Newton, the English scientist and mathematician, was one of the most important figures of the 17th century scientific revolution. One of his greatest achievement was the discovery of the three laws of motion, (26) ______ are still used today. But he also had a very unusual personality. Some people would say he was actually insane.
His father died before he was born, and his mother soon remarried. The young Isaac hated his stepfather so much that he once (27) _____ to burn his house down - when his stepfather and mother were still inside! Fortunately he did not, and he went on to graduate from Cambridge without being thrown into prison.
Isaac's first published work was a theory of light and color. When another scientist wrote a paper criticizing this theory, Isaac flew into an uncontrollable rage. The scientist (28) ______ for the criticism was a man called Robert Hooke. He was head of the Royal Society, and one of the most respected scientists in the country. (29)_______, this made no difference to Isaac, who refused to speak to him for over a year.
The simple fact was that Isaac found it impossible to have a calm discussion with anyone. As soon as someone said something that he disagreed with, he would lose his temper. For this reason he lived a large part of his life isolated from (30) ______ scientists. It is unlikely that many of them complained.
(Source: https://www.biography.com/scientist/isaac-newton)
Điền vào ô số 30
Read the following passage and mark the letter A, B, C, or D to indicate the correct word or phrase that best fits each of the numbered blanks.
Sir Isaac Newton, the English scientist and mathematician, was one of the most important figures of the 17th century scientific revolution. One of his greatest achievement was the discovery of the three laws of motion, (26) ______ are still used today. But he also had a very unusual personality. Some people would say he was actually insane.
His father died before he was born, and his mother soon remarried. The young Isaac hated his stepfather so much that he once (27) _____ to burn his house down - when his stepfather and mother were still inside! Fortunately he did not, and he went on to graduate from Cambridge without being thrown into prison.
Isaac's first published work was a theory of light and color. When another scientist wrote a paper criticizing this theory, Isaac flew into an uncontrollable rage. The scientist (28) ______ for the criticism was a man called Robert Hooke. He was head of the Royal Society, and one of the most respected scientists in the country. (29)_______, this made no difference to Isaac, who refused to speak to him for over a year.
The simple fact was that Isaac found it impossible to have a calm discussion with anyone. As soon as someone said something that he disagreed with, he would lose his temper. For this reason he lived a large part of his life isolated from (30) ______ scientists. It is unlikely that many of them complained.
(Source: https://www.biography.com/scientist/isaac-newton)
Điền vào ô số 29
Read the following passage and mark the letter A, B, C, or D to indicate the correct word or phrase that best fits each of the numbered blanks.
Sir Isaac Newton, the English scientist and mathematician, was one of the most important figures of the 17th century scientific revolution. One of his greatest achievement was the discovery of the three laws of motion, (26) ______ are still used today. But he also had a very unusual personality. Some people would say he was actually insane.
His father died before he was born, and his mother soon remarried. The young Isaac hated his stepfather so much that he once (27) _____ to burn his house down - when his stepfather and mother were still inside! Fortunately he did not, and he went on to graduate from Cambridge without being thrown into prison.
Isaac's first published work was a theory of light and color. When another scientist wrote a paper criticizing this theory, Isaac flew into an uncontrollable rage. The scientist (28) ______ for the criticism was a man called Robert Hooke. He was head of the Royal Society, and one of the most respected scientists in the country. (29)_______, this made no difference to Isaac, who refused to speak to him for over a year.
The simple fact was that Isaac found it impossible to have a calm discussion with anyone. As soon as someone said something that he disagreed with, he would lose his temper. For this reason he lived a large part of his life isolated from (30) ______ scientists. It is unlikely that many of them complained.
(Source: https://www.biography.com/scientist/isaac-newton)
Điền vào ô số 28
Read the following passage and mark the letter A, B, C, or D to indicate the correct word or phrase that best fits each of the numbered blanks.
Sir Isaac Newton, the English scientist and mathematician, was one of the most important figures of the 17th century scientific revolution. One of his greatest achievement was the discovery of the three laws of motion, (26) ______ are still used today. But he also had a very unusual personality. Some people would say he was actually insane.
His father died before he was born, and his mother soon remarried. The young Isaac hated his stepfather so much that he once (27) _____ to burn his house down - when his stepfather and mother were still inside! Fortunately he did not, and he went on to graduate from Cambridge without being thrown into prison.
Isaac's first published work was a theory of light and color. When another scientist wrote a paper criticizing this theory, Isaac flew into an uncontrollable rage. The scientist (28) ______ for the criticism was a man called Robert Hooke. He was head of the Royal Society, and one of the most respected scientists in the country. (29)_______, this made no difference to Isaac, who refused to speak to him for over a year.
The simple fact was that Isaac found it impossible to have a calm discussion with anyone. As soon as someone said something that he disagreed with, he would lose his temper. For this reason he lived a large part of his life isolated from (30) ______ scientists. It is unlikely that many of them complained.
(Source: https://www.biography.com/scientist/isaac-newton)
Điền vào ô số 27
Read the following passage and mark the letter A, B, C, or D to indicate the correct word or phrase that best fits each of the numbered blanks.
Sir Isaac Newton, the English scientist and mathematician, was one of the most important figures of the 17th century scientific revolution. One of his greatest achievement was the discovery of the three laws of motion, (26) ______ are still used today. But he also had a very unusual personality. Some people would say he was actually insane.
His father died before he was born, and his mother soon remarried. The young Isaac hated his stepfather so much that he once (27) _____ to burn his house down - when his stepfather and mother were still inside! Fortunately he did not, and he went on to graduate from Cambridge without being thrown into prison.
Isaac's first published work was a theory of light and color. When another scientist wrote a paper criticizing this theory, Isaac flew into an uncontrollable rage. The scientist (28) ______ for the criticism was a man called Robert Hooke. He was head of the Royal Society, and one of the most respected scientists in the country. (29)_______, this made no difference to Isaac, who refused to speak to him for over a year.
The simple fact was that Isaac found it impossible to have a calm discussion with anyone. As soon as someone said something that he disagreed with, he would lose his temper. For this reason he lived a large part of his life isolated from (30) ______ scientists. It is unlikely that many of them complained.
(Source: https://www.biography.com/scientist/isaac-newton)
Điền vào ô số 26