A. Binary: consists of only two kinds of atoms
· Transfer of electrons from metal to non-metals
· Electrostatic attraction of charged particles (+ and -)
· Ends in IDE
· Metal + stem of non-metal ***+ IDE
AlP- aluminum phosp + ide
Ba3N2 – barium nitr + ide
2. Writing formula
· Formula must have a net Zero charge
Ca+2 N-3 ® switch numbers (not charges) for subscripts
Na+1 Cl-1 ® no need to switch ( +1 and –1 cancel out)
Na+1 N-3 ® Na3N1, if the subscript is 1, it is not written.
Sr +2 O-2 ® SrO
****stem of common non-metals
B. Metal + polyatomic ions (p.123)
· Ends in ate or ite; exception: hydroxide, cyanide
Example: Na2SO4 sodium sulfate, NaOH sodium hydroxide
Ba(NO3)2 barium nitrate
Mg(OH)2 magnesium hydroxide
Formula must have a net Zero charge.
Ca+2 (PO4)-3 switch numbers (not charges) for subscripts
Ca3(PO4)2 ; 3 came from (PO4)-3 and 2 came from Ca+2
Na+1 (PO4)-3 switch numbers for subscripts, Na3 (PO4)1 ; remove the parenthesis and the 1 is not written, the formula is Na3PO4
3. Smallest units are IONS
COVALENT COMPOUNDS: (Molecular compound or covalently bonded compounds or molecules)
Formed by covalent bonding: sharing of electrons between nonmetals
· Ends in IDE
· Prefix (di, tri, tetra, penta,etc) name of element + prefix (mono, di, tri, etc.) + stem of non-metal ****+ IDE
· Example: NO nitrogen monoxide (note: mono is not used on the first atom); but mono is used on the second element; CO2 carbon dioxide (no mono on carbon)
H2O dihydrogen monoxide (notice mono is used on oxygen)
2. Writing: Just follow prefixes and name of elements.
· Phosphorous trichloride PCl3 Carbon tetrahydride CH4
3. Smallest Units are MOLECULES.