Bell Ringer  How do we know how many valence electrons an atom has?  What happens during ionic bonding?  What is holding an ionic molecule together?  What 2 classes of elements are involved in an ionic bond?

Covalent Bonding Chapter 6.2 a

Chemical Bonding  Ionic Bond – Force that holds cations and anions together and which involves the transfer of electrons.  Occurs between a metal and a nonmetal.

Chemical Bonding  What do you think will happen when 2 nonmetals bond?  Will there be a transfer of electrons? Why? FF

Covalent Bonding  When two nonmetals meet - one atom is NOT strong enough to take electrons from the other!  So they must share them  Covalent Bond!  Covalent bond - is a chemical bond in which two atoms share one or more pairs of valence electrons.

Covalent Bonding  Electrons want to be in pairs – 4 pairs of 2 to fulfill the octet rule.  Paired electrons are ‘happy’!  Unpaired electrons are ‘sad’

How it Works +

F F Outer Level  Still only hold 8!!!!

 All 3 figures represent the same thing!  BAR = Bond of shared electrons FF FFFF

 Diatomic means “two atoms”.  Atoms of same element share bonding electrons equally.  Balanced

The Halogen H-O-N-ies  The diatomic 7 FF  Cl  Br II HH OO NN Halogens H-O-N-ies

FFFF OR Single Bond = One Pair of e - Shared Between Two Atoms. Each atom gives one e - to the shared pair

Oxygen and Oxygen O O

OR Two Pairs of Electrons are Being Shared Each atom gives one e - to each shared pair OO OO

Nitrogen and Nitrogen N N N

OR Three Pairs of Electrons Being Shared NN NN

Practice  NCl 3  AsF 3  CF 4  CF 2 Cl 2  GeH 4  SiS 2  CH 2 O  HSiN  CSF 2  C 2 Br 2

Practice C2H6C2H4C2H2C3H8C3H4C2H6C2H4C2H2C3H8C3H4