Since there are two lone pairs on the O atom, the OF2 molecule must have a bent shape, like that of H2O. Again, all we can say about angle size is that the FOF angle should be less than 109.5 ?.
(c) The Lewis structure of AlCl4 is
-ClClAlClCl-
Since the central Al atom has no lone pairs and all four Al—Cl bonds are equivalent, the AlCl4 ion should be tetrahedral, and the ClAlCl angles should all be 109.5?.
(d) The Lewis strurcture of I3 is
III--
The central I atom has two bonding pairs and three lone pairs. From Table10-4 we see that the three lone pairs all lie in the triangular plane, and the I3 ion should be linear, like the XeF2 molecule.
3.
(a) Since N2 has one fewer electron than N2, its electron configuration is (Figures10-13)
[(σ1s)(σ
2
*2 1s+
-
)(σ2s)(σ
+
2 *2s)
2
(π
2py
)( π
2
2pz
) (σ
2
2px
)]
1
(b) The bond order of N2 is
Bond order =1/2 (9 4) =2.5
(c) N2 has one unpaired electron, so it is paramagnetic.
(d) Since the electrons in the bonding molecular orbitals are responsible for holding the atoms together, N2 should have a weaker and, therefore, longer bond than N2. (In fact, the bond length of N2 is 112 pm, compared with 110 pm for N2.)
4. There are no electronegative elements (F, O, or N) in either CH4 or Na. Therefore, only F, and HCOOH can form hydrogen bonds with water.
-+
+
+
+
__
16