chemistry note chap 11

CHAPTER 11 GROUP 14 11.1 physical properties of group 14 Electrical conductivity carbon (C)               non metal silicon  (Si)              metalloid germanium  (Ge)     metalloid tin  (Sn)                   metal lead  (Pb)                 metal Increase in number of occupied electron shell increase in electrical conductivity increase in screening effect > nuclear charge Zeff decrease (force of attraction between nucleus and valence electron weaker) Atomic radius increase Valence electron more delocalised Metallic character increase Melting point decreasing down the group C  Si  Ge  Sn  Pb highest to lowest Carbon, Silicon, Germanium giant structure strong covalent bond btw atom required lots of energy to break covalent bond high melting point and boiling point Tin, Lead Both are metals due to large atomic size, metallic bond weaker Melting and boiling points weaker Lead bigger atomic radius than tin Lead higher melting point than tin Lead more close-packed structure than tin