Atoms gain or lose electrons in chemical reactions in order to increase their energy state.

J.J. Thomson discovered that cathode rays were really a stream of electrons.

Temperature is a measure of the amount of heat stored in a substance.

The subscript “2” in Mg(OH) tells you that the charge of the hydroxide ion is (-2).

In combination reactions, elements react to form compounds.

The breaking and making of chemical bonds explains chemical reactions and energy flow.

Which of the following species is represented by the given electron configuration?

A 100-g piece of iron has twice the volume as a 50-g piece of iron.

What is the correct name for the compound, CuCl?

The symbol “∆” is used to refer to an object’s density.