Question 1

Which of the following best describes a trace element?

Accepted Answer

An element required by an organism in only minute quantities.

Question 2

Which subatomic particle determines the identity of an element?

Accepted Answer

Proton

Question 3

A radioactive isotope of carbon is used in medical imaging. What property makes it useful for this purpose?

Accepted Answer

It emits detectable radiation as it decays.

Question 4

Which of the following statements about valence electrons is correct?

Accepted Answer

They are found in the outermost electron shell and determine chemical reactivity.

Question 5

How many electrons can the first electron shell hold?

Accepted Answer

$$2$$

Question 6

Which of the following is an example of a covalent bond?

Accepted Answer

The bond between two hydrogen atoms in $$H_2$$

Question 7

What is the main difference between an ionic bond and a covalent bond?

Accepted Answer

Ionic bonds involve the transfer of electrons, while covalent bonds involve the sharing of electrons.

Question 8

Which of the following best describes a hydrogen bond?

Accepted Answer

A weak attraction between a hydrogen atom and an electronegative atom.

Question 9

Which of the following is a cation?

Accepted Answer

An atom that has lost one or more electrons and has a positive charge.

Question 10

What is the chemical formula for water?

Accepted Answer

$$H_2O$$

Question 11

Which of the following best describes chemical equilibrium?

Accepted Answer

The rate of the forward reaction equals the rate of the reverse reaction.

Question 12

A molecule of methane ($$CH_4) $$has what type of bonds between carbon and hydrogen?

Accepted Answer

Single covalent bonds

Question 13

Which of the following is NOT a van der Waals force?

Accepted Answer

Covalent bond

Question 14

If an atom has an atomic number of $$8$$ and a mass number of $$16$$, how many neutrons does it have?

Accepted Answer

$$8$$

Question 15

Which of the following best explains why water is a polar molecule?

Accepted Answer

Oxygen is more electronegative than hydrogen, creating a partial negative charge near the oxygen atom.

Question 16

Which of the following is an example of a balanced chemical equation?

Accepted Answer

$$2H_2 + O_2$ \rightarrow 2H_2O$$

Question 17

Which of the following best describes an isotope?

Accepted Answer

Atoms of the same element with different numbers of neutrons.

Question 18

Which of the following is a real-life application of using radioactive isotopes?

Accepted Answer

Dating ancient fossils using carbon-14.

Question 19

Which of the following statements about electrons is true?

Accepted Answer

Electrons are found in orbitals surrounding the nucleus.

Question 20

Which of the following best describes a chemical reaction?

Accepted Answer

The making and breaking of chemical bonds, leading to changes in the composition of matter.

Chapter 2 Elements Reviw Sheet

Study Guide - Practice Questions