Biology: Chapter 2...The Chemistry of Life

The space surrounding the nucleus of an atom contains

• protons

• electrons

• neutrons

• ions

Which of the following is a use of radioactive isotopes?

• can determine the age of rocks

• can be used to treat cancer

• used as "tracers" to follow the movement of substances in organisms

• all of the answers are correct

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.

What type of electron is available to form bonds?

• valence

• ionic

• nucleus

• covalent

What type of ion forms when an atom loses electrons?

• neutral

• negative

• positive

Ice floats on water because

• of cohesion

• ice has a higher density than water

• water shrinks when it freezes

• water expands when it freezes

The most abundant compound in most living things is

• carbon dioxide

• sodium chloride

• water

• sugar

When salt is dissolved in water, water is the

• reactant

• solute

• solution

• solvent

A substance with a pH of 6 is called

• an acid

• both an acid and a base

• a base

• neutral