Question 1

Which of the following best describes the atomic number of an element?

Accepted Answer

The number of protons in the nucleus of an atom

Question 2

A neutral atom of carbon has an atomic number of 6 and an atomic mass of 12. How many neutrons does it have?

Accepted Answer

$$12 - 6 = 6$$ neutrons

Question 3

Which of the following statements about atoms is correct?

Accepted Answer

Atoms are electrically neutral because the number of protons equals the number of electrons

Question 4

The atomic mass of an element is best defined as:

Accepted Answer

The sum of the number of protons and neutrons in the nucleus

Question 5

A sample of silver (Ag) has an atomic number of 47 and an atomic mass of 108. How many neutrons are in the nucleus of a silver atom?

Accepted Answer

$$108 - 47 = 61$$ neutrons

Question 6

Which of the following is the basic 'unit' of all matter?

Accepted Answer

Atoms

Question 7

Which of the following best explains why noble gases are generally unreactive?

Accepted Answer

Their outermost electron shell is full, making them stable

Question 8

If an atom has 17 protons, 18 neutrons, and 17 electrons, what is its atomic mass?

Accepted Answer

$$17 + 18 = 35$$

Question 9

Which of the following is true about isotopes of an element?

Accepted Answer

They have the same number of protons but different numbers of neutrons

Question 10

A helium atom has an atomic number of 2 and an atomic mass of 4. Which of the following correctly represents the number of protons, neutrons, and electrons in a neutral helium atom?

Accepted Answer

2 protons, 2 neutrons, 2 electrons

Question 11

Which of the following best describes a molecule?

Accepted Answer

A group of two or more atoms held together by chemical bonds

Question 12

Which of the following is NOT a subatomic particle found in the nucleus of an atom?

Accepted Answer

Electron

Question 13

If the atomic number of zinc (Zn) is 30, how many electrons does a neutral zinc atom have?

Accepted Answer

30

Question 14

Which of the following best explains why atoms form chemical bonds?

Accepted Answer

To achieve a full outer electron shell and become more stable

Question 15

A thallium (Tl) atom has an atomic number of 81 and an atomic mass of 204. How many neutrons does it have?

Accepted Answer

$$204 - 81 = 123$$ neutrons

Question 16

Which of the following is a correct analogy for a chemical bond?

Accepted Answer

A handshake between two people, representing shared electrons

Question 17

Which of the following is true about the mass of electrons compared to protons and neutrons?

Accepted Answer

The mass of electrons is negligible compared to protons and neutrons

Question 18

Which of the following best describes the relationship between atoms and molecules?

Accepted Answer

Molecules are formed when two or more atoms bond together

Question 19

Which of the following is the correct formula for calculating the atomic mass of an atom?

Accepted Answer

$$	ext{Atomic mass} = 	ext{Number of protons} + 	ext{Number of neutrons}$$

Question 20

Which of the following best explains why the atomic number distinguishes one type of atom from another?

Accepted Answer

Each element has a unique number of protons in its nucleus

Atoms and Molecules: Structure, Properties, and Atomic Numbers

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