Bonding 4-4

Valence Electrons Elements are arranged in the periodic table in groups Atoms properties are determined by the outer number of electrons in the cloud Valence electrons

Bonding Bonded atoms usually have a stable electron configuration Valence electrons interact Structure similar to noble gases

Bonds Bonds can be stretched without breaking Flexible rubber bands

Metals and Non-Metals

Ionic Bonds Ionic Bond – formed by attraction between oppositely charged ions Formed between: Metal Elements – positive Nonmetal Elements - negative

Ionic Bonds Formed by the transfer of electrons Instead of sharing outer most electrons they are transferred Na+ ion and Cl- ion

Ionic Compounds Na+ and Cl- form to make NaCl 1:1 Ratio for a zero charge Ca2+ and F- form to make CaF2 1:2 Ratio for a zero charge

Ionic Compounds When melted or dissolved in water ionic compounds conduct electricity Electric current – moving charges Melting points very high

Covalent Bond Covalent Bond – formed when atoms share one or more pairs of electrons Compounds made of molecules Water and sugar Nonmetal with nonmetal

Covalent Bond Most of the molecules remain intact and do not conduct electricity No charge Low melting point