Chemical BONDING
Chemical Bond A bond results from the attraction of nuclei for electrons All atoms trying to achieve a stable octet IN OTHER WORDS the p+ in one nucleus are attracted to the e- of another atom
What did the atom of fluorine say to the atom of sodium? You complete me.
Two Major Types of Bonding Ionic Bonding forms ionic compounds transfer of e- Covalent Bonding forms molecules sharing e-
IONic Bonding electrons are transferred between valence shells of atoms ionic compounds are made of ions NOT MOLECULES ionic compounds are called Salts or Crystals
[METALS ]+ [NON-METALS ]- IONic bonding Always formed between metals and non-metals [METALS ]+ [NON-METALS ]- Lost e- Gained e-
Covalent Bonding Pairs of e- are shared between non-metal atoms molecules Pairs of e- are shared between non-metal atoms forms polyatomic ions
Covalent & Ionic Bonding? NO2 sodium hydride Hg H2S sulfate NH4+ Aluminum phosphate KH KCl HF CO Co
[Na]+ [ Cl ]- NaCl This is the finished Lewis Dot Structure How did we get here?
Step 1 after checking that it is IONIC Determine which atom will be the +ion Determine which atom will be the - ion Step 2 Write the symbol for the + ion first. NO DOTS Draw the e- dot diagram for the – ion COMPLETE outer shell Step 3 Enclose both in brackets and show each charge
Always remember atoms are trying to complete their outer shell! The number of electrons the atoms needs is the total number of bonds they can make. Ex. … H? O? F? N? Cl? C? one two one three one four
Methane CH4 This is the finished Lewis dot structure How did we get here?
Step 1 count total valence e- involved Step 2 connect the central atom (usually the first in the formula) to the others with single bonds Step 3 complete valence shells of outer atoms Step 4 add any extra e- to central atom IF the central atom has 8 valence e- surrounding it . . YOU’RE DONE!
Sometimes . . . You only have two atoms, so there is no central atom, but follow the same rules. Check & Share to make sure all the atoms are “happy”. Cl2 Br2 H2 O2 N2 HCl
The End