Chemical Compounds

 

 

IONIC COMPOUND                                                                                              

Formed by ionic bond

A.   Binary: consists of only two kinds of atoms

·        Transfer of electrons from metal to non-metals

·        Electrostatic attraction of charged particles (+ and -)

1.  Naming

·         Ends in IDE

·        Metal + stem of non-metal ***+ IDE  

Ex. NaCl- sodium chlor + IDE

      AlP- aluminum phosp + ide

      Ba3N2 – barium nitr + ide

 

2.     Writing formula

·        Formula must have a net Zero charge

Ex. Calcium nitride

Ca+2    N-3  ®  switch numbers (not charges) for subscripts

  Ca3     N2  

         

          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

 

brom-bromine        nitr-nitogen

carb-carbon            hydr-hydogen

chlor-chlorine        phosph-phosphorous

iodo-iodine              sulf-sulfide

fluor-fluorine         ox-oxide

 

 

 

 

 

 

 

IONIC COMPOUND(continued)

 

B.      Metal + polyatomic ions (p.123)

·        Ends in ate or ite; exception: hydroxide, cyanide

1.       Naming

Metal + polyatomic ion name

Example: Na2SO4 sodium sulfate, NaOH sodium hydroxide

 Ba(NO3)2  barium nitrate

 

Mg(OH)2  magnesium hydroxide

 

    2.   Writing

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

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COVALENT COMPOUNDS: (Molecular compound or covalently bonded compounds or molecules)

Formed by covalent bonding: sharing of electrons between nonmetals

A.               Binary covalent compound: consists of only two kinds of atoms

·        Ends in IDE

1.                 Naming:

·        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.