$$\text{Number of neutrons} = \text{Mass number} - \text{Atomic number}$$

Question 1

Which of the following statements best describes a chemical element?

Accepted Answer

A pure substance made of only one type of atom.

Question 2

Which subatomic particle determines the atomic number of an element?

Accepted Answer

Proton

Question 3

Given an oxygen atom with a mass number of 16 and an atomic number of 8, how many neutrons does it have?

Accepted Answer

$$8$$

Question 4

Which of the following elements is NOT one of the CHNOPS elements essential for life?

Accepted Answer

Calcium

Question 5

What is the total number of electrons in a neutral carbon atom?

Accepted Answer

$$6$$

Question 6

According to the octet rule, atoms are most stable when:

Accepted Answer

Their outermost energy shell is fully occupied by electrons.

Question 7

How many valence electrons does a neutral oxygen atom have?

Accepted Answer

$$6$$

Question 8

Which of the following is true about electron energy shells?

Accepted Answer

Shells closer to the nucleus contain electrons with lower energy.

Question 9

If an atom has 7 electrons in its valence shell, what is its likely chemical behavior?

Accepted Answer

It is highly reactive and tends to gain one electron.

Question 10

Which formula correctly calculates the number of neutrons in an atom?

Accepted Answer

$$	ext{Number of neutrons} = 	ext{Mass number} - 	ext{Atomic number}$$

Question 11

Which of the following best explains why neon is chemically unreactive?

Accepted Answer

Its valence shell is fully occupied by electrons.

Question 12

How many electrons are needed for an oxygen atom to fulfill the octet rule?

Accepted Answer

$$2$$

Question 13

Which subatomic particle has no electric charge and is found in the nucleus?

Accepted Answer

Neutron

Question 14

Which of the following is a trace element required in small amounts for life?

Accepted Answer

Iron

Question 15

What is the relationship between atomic number and the number of protons in an atom?

Accepted Answer

Atomic number equals the number of protons.

Question 16

Which of the following best describes the arrangement of elements in the periodic table?

Accepted Answer

By increasing atomic number and chemical properties.

Question 17

Which of the following is the smallest unit of matter that retains the properties of an element?

Accepted Answer

Atom

Question 18

If a nitrogen atom has an atomic number of 7 and a mass number of 15, how many neutrons does it have?

Accepted Answer

$$8$$

Question 19

Which of the following statements about valence electrons is correct?

Accepted Answer

Valence electrons are found in the outermost energy shell of an atom.

Question 20

Which element has 15 protons, 15 electrons, and 16 neutrons?

Accepted Answer

Phosphorus

Introduction to Atoms, Elements, and Atomic Structure

Study Guide - Practice Questions