Question 1

Which of the following best describes why helium (He) is chemically inert?

Accepted Answer

Helium has a full outer electron shell, making it stable and unlikely to form chemical bonds.

Question 2

A sodium atom (Na) reacts with a chlorine atom (Cl) to form sodium chloride (NaCl). What type of bond is formed, and what happens to the electrons?

Accepted Answer

An ionic bond is formed; sodium donates an electron to chlorine.

Question 3

Which of the following molecules contains a nonpolar covalent bond?

Accepted Answer

Hydrogen gas ($$H_2)$$

Question 4

Why is water ($$H_2O) $$considered a polar molecule?

Accepted Answer

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

Question 5

Which of the following best explains the formation of a hydrogen bond between two water molecules?

Accepted Answer

A slightly positive hydrogen atom of one water molecule is attracted to a slightly negative oxygen atom of another water molecule.

Question 6

Which of the following is true about chemical reactions?

Accepted Answer

Chemical reactions rearrange atoms but do not create or destroy matter.

Question 7

A carbon atom has 6 protons, 6 neutrons, and 6 electrons. How many electrons are in its valence shell?

Accepted Answer

4

Question 8

Which of the following best describes a double covalent bond?

Accepted Answer

Two atoms share two pairs of electrons.

Question 9

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

Accepted Answer

Table salt ($$NaCl)$$

Question 10

Which statement best explains why methane ($$CH_4) is a $$nonpolar molecule?

Accepted Answer

The electrons are shared equally between carbon and hydrogen atoms.

Question 11

If an atom has 7 electrons, how are they distributed in its electron shells?

Accepted Answer

2 in the first shell, 5 in the second shell

Question 12

Which of the following best describes the difference between a molecule and a compound?

Accepted Answer

A molecule is formed by covalent bonds, while a compound is formed by atoms of different elements.

Question 13

Which of the following best explains why sodium (Na) is highly reactive?

Accepted Answer

It has one electron in its outermost shell, which it readily loses to achieve a full shell.

Question 14

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

Accepted Answer

The bond between oxygen and hydrogen in a water molecule ($$H_2O)$$

Question 15

Which of the following statements about hydrogen bonds is correct?

Accepted Answer

Hydrogen bonds are weak attractions between a hydrogen atom with a partial positive charge and another atom with a partial negative charge.

Question 16

Which of the following best describes what happens during the formation of a water molecule from hydrogen and oxygen gases?

Accepted Answer

Covalent bonds form between hydrogen and oxygen atoms, creating $$H_2O.$$

Question 17

Which of the following is true about the reversibility of chemical reactions?

Accepted Answer

Products of the forward reaction can become reactants for the reverse reaction.

Question 18

Which of the following best explains why chlorine (Cl) becomes negatively charged when forming an ionic bond with sodium (Na)?

Accepted Answer

Chlorine gains an electron from sodium, resulting in a negative charge.

Question 19

Which of the following is a correct statement about valence electrons?

Accepted Answer

Valence electrons are found in the outermost electron shell and are involved in chemical bonding.

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

Study Guide - Practice Questions