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

Question 1

Which of the following elements is NOT one of the six most abundant elements in living organisms, commonly referred to as CHNOPS?

Accepted Answer

Calcium

Question 2

What is the correct formula to calculate the number of neutrons in an atom?

Accepted Answer

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

Question 3

Which statement best explains why Carbon-14 is useful for dating ancient fossils?

Accepted Answer

It is a radioactive isotope that decays at a predictable rate.

Question 4

An atom of oxygen has an atomic number of 8 and a mass number of 16. How many neutrons does it have?

Accepted Answer

8

Question 5

Which of the following best describes a cation?

Accepted Answer

An atom that has lost electrons and has a positive charge.

Question 6

According to the octet rule, how many electrons are needed to fill the valence shell of an oxygen atom?

Accepted Answer

2 (since oxygen has 6 valence electrons and needs 2 more to reach 8)

Question 7

Which of the following is TRUE about isotopes of the same element?

Accepted Answer

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

Question 8

If the half-life of Carbon-14 is 5,730 years, how many years must pass for a sample to decay to one-fourth of its original amount?

Accepted Answer

11,460 years

Question 9

Which of the following statements about electron shells is correct?

Accepted Answer

Valence electrons are found in the outermost shell.

Question 10

A neutral atom of nitrogen has an atomic number of 7. According to the octet rule, what is the electron distribution in its shells?

Accepted Answer

2, 5

Question 11

Which of the following is NOT a use of radioactive isotopes?

Accepted Answer

Increasing the stability of chemical compounds

Question 12

How are Carbon-13 and Nitrogen-15 isotopes different from the more abundant Carbon-12 and Nitrogen-14 isotopes?

Accepted Answer

Each has one extra neutron.

Question 13

Which of the following best describes a hydrogen bond?

Accepted Answer

A weak interaction between a hydrogen atom and a highly electronegative atom like oxygen or nitrogen.

Question 14

What is the atomic number of an element equal to?

Accepted Answer

The number of protons in the nucleus.

Question 15

Which of the following statements about valence electrons is correct?

Accepted Answer

Valence electrons determine the chemical reactivity of an atom.

Question 16

Which of the following is the correct chemical formula for glucose?

Accepted Answer

$$\mathrm{C_6H_{12}O_6$}$$

Question 17

Which of the following is TRUE about trace elements?

Accepted Answer

They are required in small amounts for life.

Question 18

Which of the following best describes an isotope?

Accepted Answer

Atoms of the same element with different numbers of neutrons.

Question 19

Which of the following statements about the periodic table is correct?

Accepted Answer

It arranges elements based on their chemical properties.

Question 20

Which of the following is a correct statement about the first energy shell of an atom?

Accepted Answer

It can hold up to 2 electrons.

Atoms, Elements, and Atomic Structure: General Chemistry Study Notes

Study Guide - Practice Questions