Question 1

Which of the following best describes a compound?

Accepted Answer

A substance consisting of two or more different elements combined in a fixed ratio.

Question 2

Which of the following elements is NOT one of the four that make up 96% of living matter?

Accepted Answer

Calcium

Question 3

A trace element is best defined as:

Accepted Answer

An element required by an organism in very small quantities.

Question 4

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

Accepted Answer

Elements in the same group have the same number of valence electrons.

Question 5

What is the atomic number of an element?

Accepted Answer

The number of protons in the nucleus.

Question 6

Which of the following best explains why sodium (Na) and chlorine (Cl) form an ionic bond?

Accepted Answer

Sodium transfers an electron to chlorine, forming oppositely charged ions.

Question 7

Which of the following molecules contains a nonpolar covalent bond?

Accepted Answer

$$\mathrm{O_2$}$$

Question 8

What is the main reason water molecules are attracted to each other?

Accepted Answer

Hydrogen bonds form between the partially positive hydrogen of one molecule and the partially negative oxygen of another.

Question 9

Which of the following best describes a polar covalent bond?

Accepted Answer

Electrons are shared unequally, resulting in partial charges.

Question 10

A molecule of carbon dioxide ($$\mathrm{CO_2$}) $$contains which type of bond between carbon and oxygen?

Accepted Answer

Double nonpolar covalent bond

Question 11

Which of the following is a correct statement about hydrogen bonds?

Accepted Answer

They are intermolecular bonds that form between polar molecules.

Question 12

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

Accepted Answer

They have a full valence shell of electrons.

Question 13

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

Accepted Answer

$$16 - 8 = 8$$ neutrons

Question 14

Which of the following is an example of a trace element and its biological role?

Accepted Answer

Iron (Fe): Required for oxygen transport in blood

Question 15

Which of the following best describes the octet rule?

Accepted Answer

Atoms will gain, lose, or share electrons to complete their valence shell with 8 electrons.

Question 16

Which of the following scenarios best illustrates the formation of a cation?

Accepted Answer

A sodium atom loses an electron to become $$\mathrm{Na^+}.$$

Question 17

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

Accepted Answer

Oxygen is more electronegative than hydrogen, causing unequal sharing of electrons.

Question 18

Which of the following is a real-life example of an ionic compound?

Accepted Answer

Table salt ($$\mathrm{NaCl})$$

Question 19

Which of the following statements about electronegativity is correct?

Accepted Answer

Electronegativity increases from left to right across a period.

Question 20

A molecule of nitrogen gas ($$\mathrm{N_2$}) $$contains which type of bond?

Accepted Answer

Triple nonpolar covalent bond

The Chemical Context of Life: Elements, Atoms, and Chemical Bonds

Study Guide - Practice Questions