Ionic/Covalent Bonding Notes

Stable or Unstable? An atom is only stable if it has a full valence shell If an atom is stable, it will not bond If an atom is not full, it will bond

Compounds Compounds are formed when 2 atoms of different elements bond together. Atoms bond to fill their valence shell An atom will bond with an many atoms as it takes to fill its outer shell Once the valence shell is full, that atom is stable

Types of Chemical Bonds There are two types of chemical bonds: Ionic Bonds Covalent Bonds

Ionic Bonds Ionic bonds exist between a non- metal and a metal When two atoms bond ionically, they gain/lose electrons When an atom gains or loses an electron, it becomes an ion

Ions Ca +2 +2 +2 +2 +2 +2 +2 It has 2 valence electrons. How many does it need to be stable? 8…so it can either lose 2 or gain 6. Which is easier? Calcium is in group 2. How many valence electrons does it have? Which other elements would lose 2 electrons? Group 1 18 2 13 14 15 16 17 3 4 5 6 7 8 9 10 11 12 Losing 2…if it loses 2 electrons, it becomes positive Ca +2 +2 +2 +2 +2 +2 +2

Ions +1 +1 +2 +3 +4 -3 -2 -1 +1 -2 +2 +3 +4 -3 -1 +1 -2 +2 +3 +4 -3 -1 Group 1 18 2 13 14 15 16 17 3 4 5 6 7 8 9 10 11 12 +1 +1 +2 +3 +4 -3 -2 -1 +1 -2 +2 +3 +4 -3 -1 +1 -2 +2 +3 +4 -3 -1 +1 +2 +3 +4 -3 -2 -1 +1 +2 +4 -3 -2 -1 +3 +1 +2

Ionic Bonds Properties of Ionic Compounds High melting point Good conductor of electricity Solid at room temperature

Covalent Bonds Covalent bonds exist between NONMETAL and NONMETAL. Example: H2, H2O, NO3, CH4 Covalent bonds SHARE electrons. Shared electrons don’t belong to either atom.

Covalent Bonds Properties of Covalent Compounds Low melting point Poor conductor of electricity Liquid or Gas at room temperature