4 – Investigate and describe the compounds formed by bonding elements. 3 – Describe why certain elements bond with others. 2 – Use the periodic table to identify the number of protons, neutrons, or electrons in an element. 1 – Identify patterns on the periodic table.

 Ion – atom or group of atoms that has an electric charge  Ionic bonds form when atoms gain or lose electrons (between metals and nonmetals).  When an atom loses an electron, it becomes a positive ion. Ex. Li+  When an atom gains an electron, it becomes a negative ion. Ex. Cl-

 A compound that consists of ions is called an ionic compound.  The name of the positive ion comes first, followed by the name of the negative ion. (This means metal before nonmetal or metalloid, left before right)

 A covalent bond is formed when two atoms share electrons.  Covalent bonds usually form between two or more nonmetals.  A molecule is a neutral group of atoms joined by covalent bonds. Ex. H 2 O

 A metallic bond is formed when many metal atoms share their pooled valence electrons.

4 – Investigate and describe the compounds formed by bonding elements. 3 – Describe why certain elements bond with others. 2 – Use the periodic table to identify the number of protons, neutrons, or electrons in an element. 1 – Identify patterns on the periodic table.