Chemical Bonds. A chemical bond forms between two atoms when valence electrons move between them Two main types of chemical bonds Covalent Bonds : occur between atoms when valence electrons are shared . Ionic Bonds : occur when valence electrons are transferred ( stolen ) between atoms
A metal and a nonmetal will form Ionic Bonds when chemically bonded together!!
NTK - “Polyatomic” ions
Carbon can form 4 bonds
Chlorine can form 1 bond
Oxygen can form 2 bonds
Two or more nonmetals will form Covalent Bonds when chemically bonded together!!
Reactant + Reactant Product + Product
It’s best to list the # of atoms under the molecules as we are doing in these examples
This reaction IS NOT balanced
4 Reactant Hydrogens = 4 Product Hydrogens
2 Reactant Oxygens = 2 Product Oxygens
This reaction is balanced!
Step 1: Count the atoms on both sides of the equation & compare
** you can only add or change whole # coefficients to balance equations. Never change subscripts
Step 2: apply a coefficient to a molecule to balance an “easy” atom (in this case, we can add a 2 coefficient to the product water to balance the H’s)
Step 3: Recount
Step 4: apply a coefficient to a molecule to balance the next off balanced atom (in this case, the oxygens are not yet balanced. We can add a coefficient of 2 in front of the reactant oxygen to correct this)
Step 5: Recount
Step 6: Continue doing this until all atoms are balanced
2H2 + O2 2H2O
2H2O 2H2 + O2
2CuO + C 2Cu + CO2
NaCl + Pb(NO3)2 NaNO3 + PbCl2