chemistry chemistry asking 20p

1.
hydrogen iodide REALLY does not obey octet rule.
iodine has eight electrons in outermost shell; everyone got it.
oh but please remember, hydrogen DOES NOT !!
H has 2 electrons, thus is duet / doublet. similar case is helium and lithium ion.


2.
P has 5 valence electrons.
if X obeys octet rule, then 3 electrons are involved in single bond-formation with Cl ; PCl3 is resulted.
3 bond-pairs and 1 lone pair, shape expected is trigonal pyramid (like :NH3) by VSEPR; bond angle expected (naively) would be109.5 degree.

if Y is a hypervalent compound, all 5 electrons forms P-Cl bond, it'd be PCl5 .
5 bond-pairs and no lone-pair, it'd be trigonal bipyramid. bond angle between axial & equatorial P-Cl is 90*, that between two equatorial P-Cl is 120*.


3.
like water, O in the molecule has 2 bond pairs (H-O, O-O) and 2 lone pairs. these 4 pairs would adopt tetrahedral arrangement, yielding V-shape among these 3 atoms.
bod angle of H-O-O would primarily be 109.5*, yet bond pair-lone pair repulsion is stronger than bp-bp repulsion. the bonds are "squeezed" together, yielding bond angle lower than expected.

(but still, there're some other factors affecting the bond angle in H2O2, quite advance level in inorganic chem....)

HI molecule obeys octet rule.

想問下第一題個HI 係 指hydrogen iodide gas 定係 hydroiodic acid?

2011-08-19 12:22:59 補充：
As I remember, the bond angle of H2O2 is not 104. Any mistake?