Question 1

Which of the following best describes an isotope?

Accepted Answer

Atoms of the same element with different numbers of neutrons.

Question 2

Which of the following statements about electron shells is correct?

Accepted Answer

The first electron shell can hold up to 2 electrons.

Question 3

A sodium atom (Na) has an atomic number of 11 and a mass number of 23. How many neutrons does it have?

Accepted Answer

$$23 - 11 = 12$$

Question 4

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 oxygen.

Question 5

What type of bond is formed when two atoms share electrons equally?

Accepted Answer

Nonpolar covalent bond

Question 6

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

Accepted Answer

The attraction between a hydrogen atom of one water molecule and the oxygen atom of another water molecule.

Question 7

If an atom has 6 protons, 6 neutrons, and 6 electrons, what is its atomic number and mass number?

Accepted Answer

Atomic number = 6, Mass number = 12

Question 8

Which of the following best describes a covalent bond?

Accepted Answer

A bond formed by the sharing of electrons between atoms.

Question 9

Why is the electron configuration of chlorine (Cl) with 2 electrons in the first shell, 8 in the second, and 7 in the third shell correct?

Accepted Answer

Because chlorine has 17 electrons, which fill the shells as 2, 8, and 7.

Question 10

Which of the following is true about potential energy in electrons?

Accepted Answer

Electrons in the outermost shell have the highest potential energy.

Question 11

Which of the following best describes an ionic bond?

Accepted Answer

A bond formed by the transfer of electrons from one atom to another.

Question 12

How many covalent bonds can a carbon atom typically form?

Accepted Answer

4

Question 13

Which of the following is a real-world example of an ionic bond?

Accepted Answer

The bond between sodium and chlorine in table salt (NaCl).

Question 14

Which of the following statements about valence electrons is correct?

Accepted Answer

Valence electrons are responsible for the chemical properties of an atom.

Question 15

What is the maximum number of electrons that can occupy the second electron shell?

Accepted Answer

8

Question 16

Which of the following best explains why noble gases are chemically inert?

Accepted Answer

They have full outer electron shells.

Question 17

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

Accepted Answer

The bond between hydrogen and oxygen in water (H$$_2O).$$

Question 18

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

Accepted Answer

The atomic number is equal to the number of protons.

Question 19

Which of the following is a correct Lewis structure for a water molecule (H$$_2O$$)?

Accepted Answer

H-O-H with two pairs of non-bonding electrons on the oxygen atom.

Question 20

Which of the following best describes the difference between kinetic and potential energy in biological systems?

Accepted Answer

Potential energy is stored energy, while kinetic energy is energy of motion.

The Chemical Context of Life: Study Guide and Review

Study Guide - Practice Questions