Covalent Bond

You need to know that a bond contains two eletrons

simple bond
e.g. iodine 2,8,7 I－I
it needs to share 1 electron, therefore in a iodine molecule,
there are two electrons are sharing each other, and then we have a single bond

double bond
e.g. oxygen 2,8,6 O＝O
it needs to share 2 electron, therefore in a oxygen molecule,
there are four electrons are sharing each other, and then we have a double bond

triple bond
e.g. nitrogen 2,5 N≡N
it needs to share 3 electron, therefore in a nitrogen molecule,
there are six electrons are sharing each other, and then we have a triple bond

2007-10-13 21:20:42 補充：
there are X electrons sharing each other...NO the second 'are'.. sorry for the mistake =V="A bond = a pair

simple bond係 c-c(一對share e-)
double bond係c=c(兩對share e-)
triple bond 係 c_=c(三對share e-)