Question 1

Which subatomic particle is responsible for the identity of an element, and what is its charge?

Accepted Answer

Proton; charge +1

Question 2

Given an atom of Zinc with 30 protons and 35 neutrons, what is its atomic representation using the format $$\mathrm{^{A}_{Z}X}$$?

Accepted Answer

$$\mathrm{^{65}_{30}Zn}$$

Question 3

Which force is primarily responsible for holding protons and neutrons together in the nucleus despite electrostatic repulsion?

Accepted Answer

Strong nuclear force

Question 4

A neutral atom of Copper has a mass number of 64. How many neutrons does it contain?

Accepted Answer

35

Question 5

Which statement best explains why electrons do not collapse into the nucleus?

Accepted Answer

Electrostatic attraction is balanced by the electrons' kinetic energy and quantum effects.

Question 6

What is the charge and relative mass of a neutron?

Accepted Answer

Charge: 0, Mass: 1

Question 7

If an atom has 15 protons, 16 neutrons, and 15 electrons, what is its atomic number and mass number?

Accepted Answer

Atomic number: 15, Mass number: 31

Question 8

Which of the following best describes the electron cloud in an atom?

Accepted Answer

A region where electrons move very fast and are widely spaced

Question 9

Why do unstable nuclei decay over time?

Accepted Answer

Because they have unbalanced forces between electrostatic repulsion and strong nuclear force

Question 10

Which of the following is true about elements?

Accepted Answer

Each element is given a symbol on the periodic table

Question 11

A lead atom has a mass number of 207 and 82 protons. What is its atomic representation?

Accepted Answer

$$\mathrm{^{207}_{82}Pb}$$

Question 12

Which of the following pairs will experience electrostatic repulsion?

Accepted Answer

Proton and proton

Question 13

What is the mass (in kg) of an electron?

Accepted Answer

$$9.109 	imes 10$$^{-31}$$

Question 14

Which statement best describes the strong nuclear force?

Accepted Answer

It is responsible for holding the nucleus together by acting between all nucleons

Question 15

If an atom has 29 electrons and a mass number of 64, what is its atomic number and how many neutrons does it have?

Accepted Answer

Atomic number: 29, Neutrons: 35

Question 16

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

Accepted Answer

Electron

Question 17

What is the main reason the nucleus occupies a very small fraction of the atom's volume?

Accepted Answer

Because the electron cloud is much larger and more diffuse

Question 18

Which of the following best describes the relationship between atomic number and element identity?

Accepted Answer

Atomic number is the number of protons and defines the element

Question 19

Which of the following would result if the strong nuclear force did not exist?

Accepted Answer

Nuclei would not be stable and protons would repel each other, causing the nucleus to fall apart

Question 20

Which of the following is the correct symbol for an atom with 15 protons and 16 neutrons?

Accepted Answer

$$\mathrm{^{31}_{15}P}$$

Atoms and Elements: Foundations of General Chemistry

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