Ionic bonds

Group 1

Metals with one valence electron; these metals readily lose their electron to form positive ions. (+1)

Group 2

Metals with two valence electrons; these metals readily lose their electrons to form positive ions. (+2)

Group 3

Metals with three valence electrons; these metals tend to lose their electrons to form positive ions. (+3)

Group 5

Nonmetals with five valence electrons; these elements typically gain three electrons to form negative ions. (-3)

Group 6

Nonmetals with six valence electrons; these elements usually gain two electrons to form negative ions. (-2)

Group 7

Nonmetals with seven valence electrons; these elements typically gain one electron to form negative ions. (-1)

Transition metals

Large block in the middle of the periodic table that generally form +2 ions.

1:1 ratio

Ionic compounds from ions that combine in equal proportions. For example; +1 with -1, or +2 with -2

1:2 ratio

Ionic compounds formed from ions that combine in a two-to-one proportion, such as +2 with -1, or +1 with -2.

Criss cross method

The charge of one ion becomes the subscript of the other ion when writing the formula of an ionic compound. For example:

Ca⁺² with Cl^-1 has the chemical formula CaCl₂

Ionic compound properties

Ionic compounds typically have high melting and boiling points, are solid at room temperature, and conduct electricity when dissolved in water or melted.

Ionic bond

Formed through the attraction between oppositely charged ions; a metal (+ion) will bond with a nonmetal (-ion).

Subscript

Indicates the number of atoms of an element in a chemical formula. Written as a small number to the right of the element's symbol.

Superscript

Indicates the charge of an ion in a chemical formula, written as a small number above and to the right of the element's symbol.