Nurrr" KFV
Lab Section Number
Chemistry 4A Midterm
/ GS:
2
Please write your answers with pen or dark pencil. Answers will be graded only
the space provided. Extra work area is provided at the back of the exam.
L. Graph the radial distribution functions for
each diagram with the orbital name. "
within
2s, 2p, a,rid 3p orbitals. Be sure to label
r.
2. List the quantum numbers and state what they represent classically. Which
quantum number lacks a classical analos-v?
n
,r\4tl lt',,r1l (ri*t\
c^t"lk, I - ggntr. rnjnrr.Juq. 6Lyt)
rl1adrq
*f-li^ hriat4;^i^ rrar)
'\
grlndsa!,
rpr'n,
{l
5
C.&tder!
t.^tJllft
why are the s and p orbitals of different energy in a non-hydrogenic atom?
Explain using radial distribution functions.
f.r
l&-,
L^-
h
d"
{"
s crl,td crfa&d) h &ttr
.||t
^reft.o.
te sUdA
{lr
I+
Irl*'{iftl(v #r r},.1o.0 ir
rtud&J
fu e f*qi of +h 2s
or lr.la.0.
o**0 .tlcf 4}e gytda goiat o&c
t
4{ nqchur &.. 'hr.t*f ryq^).
?tri ltcnrrer .t{t Lrr httth*l
29 qrr"{a0. )f{ tt o.h{ql
ir n* .t'*dd q *t ?9 srbt\aL,
r*4 +1+ lr b,,rr i^ ,Nft,
\ {
4. Rank the following
atoms or ions from highest ionization energy to lowest: AI, Ne,
F-, B, O'
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ft
l^ E ld:
A
v
*r
(o0
3I8
--S
,et0
!ilb/€tT
t
I 3^t
I
F3{r
*rr
- ct4lt-'q)
(,q.
5. Explain, using arguments related to screening and radial distribution functions in
atoms, why Ne has zero electron affimty.
- /t
-1
hr,
.& b 6r{ L2 or}il.l, *ttrt.
(3r) to a, nd/l, n6#hJirr.
+trdlr et* +t *Ana +cr+{r &n* {t -n^rcitrrr,
- "rn !r oebid t elkct,4t t ssqrtrd h *t 2r, 1l *U*.
- 5i... t Crc*p s *2rclwrq {* tA k tft*r,
tryf rgur oe li'lal
-Yl.it p{r
{h
chr4n,1-
i.fi;r tta^t Ptrln
'.
* t rr'ri t /& A ex7r,
6. Draw the Lewis dot structure for the cyanide anion (CN-), including all
lone pairs, and formal cha,rses.
rc=.f{:
bonds,
cr CN
5
G<;a?+* 5*t,sctrrre
*\
Lrr{rs.\5 {Lc*o\
-3
y'.o\ate5
*3
b no \tigr'
*i
FP t@ lec\ti.5 \un-
a\n".
ack'\
?
fo\*
b"nS
O^
l^,n
r.toc*
O i^ co'rt*-\
(a) What is the bond order?
7"
!orrcd
I
i^co(c"'\
3
6\
bv\
rnc^t.Lt.s
c-7'<'
\ tr cgrrq't
(b) State whether the bonds are either o or ir.
i
z
Ia
2f
\<r bora+
2n H&*
LtnAs
(c) Aroun4 which atom do you expect the extra electron to be localized?
tf
',"rn
ctrlm,r1*l'*
, $r<cux
N - mocs e\qt
oc
C
'b"-
r
or {\os
L- lno
dir.
rt.^\
cc
cha.c5*
O lnc"$'-\
\e^\""'*
Sscmr^\ itaatn6'
7. Why
does w.qter responds
to
a charged rod,
but hexane doesn't?
['
ll
n
r+
r+ ,/i\*
,f
,rc\ c-,cHl
-cr e{ '{ ooLp&.
tr.'
trlt
q$
ultr rtlpildt h a tufd '* bceatatt * F ^ .. i
'. '!)ttQ' ;t o i;5 * lJcr'mrr lT tlldldtyJinfiJ '
$*
bi 0"*-+
a^l ,1, b"t ,*l'ir..0 'Lllg'hu b&' ll ad C.
YLir fite ,u,r*ht or.tl<r q^ rkclt i'dl ''4rf u't*
h &tqd/ 6c ,earful f t' ehr.fl lrd-
Draw the molecular orbital energy level diagram for 02 (where there is no s-p
mixing) and fill in the valence electrons. In the diagram, label atomic energy levels
their atomic orbitals and the molecular energy levels with o, T, o*, and zr*.
.''--7".
I
r--
--_ _ 4
4t J- J-r-:.";)'-
\
- fri'+t.--. tlt ,l
1
CL
lr
1L
t9--v---
-J
qf
r-
- s \
-t-
--- _!_u
(a) Calculate the bond order for
Oz.
'ry=El
(b) How many electrons would have to be promoted to the nearest, higher energy
molecular orbltals in older for the O2 molecule to dissociate?
9. The following
concern the molecule formaldehyde, CH2O:
(a) Draw out the Lewis
including lone pairs and bonds.
:0\
tl
/c\,
il^t
(b) What is thg VSEPR predicted geometry?
*r;gorcl /a"sr
(c) For this geometry draw out the o bond framework for C and o and state
how the s-p orbitals are hybridized.
o
c, sf'
6
e
re@'%,
(d) How
ma,ny zr bonds are there and between which atoms?
I
I bd.an 0 ,rd
C