Draw Lewis structure of CO2  i)  Valence electrons:  4 + 2 x 6 = 16 ( 8 pairs) ii)  Central atom  C;             O -- C -- O iii)  Give octet to carbon                                     --                              O -- C -- O                                     --  Try to fill octet to O  iv)  Count electrons: 4 bond pairs = 4 pairs        4 lone pairs  = 4 pairs                                8 electron pairs