2010-2023 Chapter 2 - The Chemistry of Life

The space surrounding the nucleus of an atom contains

• protons.
• neutrons.
• electrons.
• ions.

The nucleus is made up of

• protons and electrons.
• protons and neutrons.
• electrons and neutrons.
• protons, neutrons, and electrons.

Isotopes are atoms of the same element with the same number of protons and

• a different number of electrons.
• a different number of neutrons.
• a different number of molecules.
• the same number of neutrons.

Which of the following is a use of radioactive isotopes?

• can determine the ages of rocks and fossils
• can be used to treat cancer and kill bacteria that cause food to spoil
• can be used as “tracers” to follow the movements of substances within organisms
• All are uses.

Which of the following terms describes a substance formed by the combination of two or more elements in definite proportions?

• compound
• nucleus
• isotope
• enzyme

Which of the following makes up a molecule of water?

• one atom of hydrogen and one atom of oxygen
• one atom of sodium and one atom of chlorine
• one atom of hydrogen and two atoms of oxygen
• two atoms of hydrogen and one atom of oxygen

Which of the following statements about a compound is true?

• The physical and chemical properties of a compound are usually very different from those of the elements from which it is formed.
• Only the physical properties of a compound are usually the same as those of the elements from which it is formed.
• Only the chemical properties of a compound are usually the same as those of the elements from which it is formed.
• The physical and chemical properties of a compound are usually the same as those of the elements from which it is formed.

A covalent bond is formed as the result of

• transferring electrons.
• transferring protons.
• sharing an electron pair.
• sharing a proton pair.

The most abundant compound in most living things is

• carbon dioxide.
• sodium chloride.
• water.
• sugar.

Water molecules are polar, with the

• oxygen side being slightly positive and the hydrogen side being slightly negative.
• oxygen and hydrogen sides being slightly positive.
• oxygen and hydrogen sides being slightly negative.
• oxygen side being slightly negative and the hydrogen side being slightly positive.