Chapter 2: Chemistry

How do ions form ionic bonds?

Ions of opposite electrical charges are attracted to each other to balance the charges.

Which of the following statements is true regarding the enzyme-catalyzed reaction compared to the uncatalyzed reaction?

Less energy input is required to start the reaction in the presence of enzyme.

Which of the following is an example of a decomposition reaction?

MgO2 → Mg + O2

Atoms of oxygen have a total of 8 electrons. Are these atoms stable, and why or why not?

No, because the atoms have only 6 valence electrons, but need 8 for stability.

Which of the following distinguishes hydrogen bonds from covalent bonds?

Only hydrogen bonds can form between molecules.

What explains the negative charge on the oxygen atom within the water molecule?

Oxygen atoms have a stronger pull on the electrons shared within a covalent bond formed between oxygen and hydrogen.

Which of the following is not a result of hydrogen bonds?

Two hydrogen atoms join together to form a molecule of hydrogen gas.

Carbon atoms have four valence electrons. Are they likely to react with other atoms, and why or why not?

Yes, because they can become more stable by doing so.

What is an ion?

an atom that has either gained or lost electron(s)

Which of the following is not produced through chemical bonding?

atoms

Which subatomic particles contribute to an atom's mass number but not its atomic number?

neutrons

Which of the following is NOT a compound?

oxygen gas

Formation of hydrogen bonds requires hydrogen atoms and what else?

polar covalent

Which type(s) of subatomic particles can be located within the nucleus of an atom?

protons and neutrons

When an ionic bond forms, which part(s) of the atoms are directly involved?

the outermost electrons

Which parts of atoms can interact (react) to form chemical bonds?

valence electrons

Calcium's atomic number is 20. It forms ions with 18 electrons. What is the electrical charge of a calcium ion?

+2

An atom of oxygen has an atomic number of 8 and a mass number of 18. How many of each type of subatomic particle does it contain?

8 protons, 8 electrons, and 10 neutrons

What is the primary energy-transferring molecule in cells?

ATP

In a covalent bond,

Atoms share one or more pairs of electrons.

Which of the following correctly ranks the types of chemical bonds, in order, from strongest to weakest?

covalent, ionic, hydrogen