7 1 NOTES Intro to Covalent Bonding Ionic

7. 1 – NOTES Intro to Covalent Bonding

Ionic Bonding Review • At this point in time we have covered the naming of substances held together by an ionic bond. • Bonded by opposite charges, one positive and one negative • Often a metal and a nonmetal • There are other ways to bond atoms together such as a covalent bond.

• I. The Covalent Bond • A. Why do atoms bond? Obtain the e- configuration of a noble gas; • 8 outer e-; octet rule; • B. What is a covalent bond? • Formation of a covalent bond – bond in which atoms share electrons; - shared electrons are counted as valence e- for each atom; formed between two nonmetallic elements; - when electrons are shared a molecule is formed - lone pairs – unshared pairs of e-

• II. Naming molecules • A. Naming binary molecular compounds • Use prefixes to indicate how many of each atom are present. • The first element keeps its name and has a prefix if more than one atom is present. The second atom will end in –ide and always has a prefix. • • 1 – mono 2 – di 3 – tri 4 – tetra 5 – penta • 6 – hexa 7 – hepta 8 – octa 9 – nona 10 – deca

• Examples: • NO • nitrogen monoxide • PCl 5 • phosphorus pentachloride • N 2 O 3 • dinitrogen trioxide • B. Common names of some molecular compounds • Methane – CH 4 Ammonia – NH 3