Electron Configuration & Resonance DAT

[ieutront]

The electronic configuration of a particular neutral atom is 1s2 2s2 sp6 3s2 3p2. What is the number of unpaired electrons in this atom?

a. 1
b. 2
c. 3
d. 4
e. 0

The answer is 3. I am not sure why. Does the empty orbital of P count as an unpaired electron?

another question:

the lewis structure for NO3 minus. which looks like this O-N=O and another O single bond attached to it. The total number of ground state resonance structures for this ion is?

Answer is 3. I was wondering is the third resonance structure a hybrid? Thanks.

[joonkimdds]

Originally Posted by ieutront

The electronic configuration of a particular neutral atom is 1s2 2s2 sp6 3s2 3p2. What is the number of unpaired electrons in this atom?

a. 1
b. 2
c. 3
d. 4
e. 0

The answer is 3. I am not sure why. Does the empty orbital of P count as an unpaired electron?

1s2 2s2 sp6 3s2 3p2. ????
what's sp6?
I wonder if sp6 is what 4 year institutions teach but as a community college student let me assume it's 2p6.
P has 3 blanks. when it has 6 arrows in it, the order u draw is up up up and then down down down. In ur question, it says 3p2, so u draw up up. therefore, none of the 3 blanks have pair in it, and 3 is the answer.

[ieutront]

Originally Posted by joonkimdds

1s2 2s2 sp6 3s2 3p2. ????
what's sp6?
I wonder if sp6 is what 4 year institutions teach but as a community college student let me assume it's 2p6.
P has 3 blanks. when it has 6 arrows in it, the order u draw is up up up and then down down down. In ur question, it says 3p2, so u draw up up. therefore, none of the 3 blanks have pair in it, and 3 is the answer.

yeah its actually 2p6. I typed it wrong. anyway, thats what I was thinking as well. Thanks.

[Denro]

Originally Posted by ieutront

The electronic configuration of a particular neutral atom is 1s2 2s2 sp6 3s2 3p2. What is the number of unpaired electrons in this atom?

a. 1
b. 2
c. 3
d. 4
e. 0

The answer is 3. I am not sure why. Does the empty orbital of P count as an unpaired electron?

another question:

the lewis structure for NO3 minus. which looks like this O-N=O and another O single bond attached to it. The total number of ground state resonance structures for this ion is?

Answer is 3. I was wondering is the third resonance structure a hybrid? Thanks.

wait a min. shouldnt the answer be 2. b.c 3p2 has two unpaired electrons in the p orbital

[rals]

Originally Posted by Denro

wait a min. shouldnt the answer be 2. b.c 3p2 has two unpaired electrons in the p orbital

yea, it should be 2 ... |^ _|^ _|_ _|

and about the resonance question, it's three because there are 3 o's that have identical electronegativities and therefore contribute equally to a hybrid. basically, the double bond can be moved around to each of the three o's.

[Pelotari]

I am not quite convinced that empty shells are the same as unpaired electrons. These are energy levels waiting to be "filled".

I would take a different approach. Look at the valance shells:

1s is complete (two electrons).
2s is complete and 2p is complete (octet).
3s is complete, and 3p is not complete (has only two, needs 6 more to complete the octet).

Thus, the only unpaired electrons are two and the answer should be "b" (in my humble opinion).

[Pelotari]

Originally Posted by Pelotari

I am not quite convinced that empty shells are the same as unpaired electrons. These are energy levels waiting to be "filled".

I would take a different approach. Look at the valance shells:

1s is complete (two electrons).
2s is complete and 2p is complete (octet).
3s is complete, and 3p is not complete (has only two, needs 6 more to complete the octet).

Thus, the only unpaired electrons are two and the answer should be "b" (in my humble opinion).

One clarification: above I said that for n=3 (i.e. 3s and 3p), you needed six to complete the octet. Actually, you need 4 more (not six) to complete it. Still, your only available electrons are two. Answer is the same.

[ieutront]

well this is from the ADA sample test, and the answer for it was 3. I thought the same as you guys but thats what it is and was wondering if someone on sdn could explain. oh yeah, i already took my test. this question is not on it so no worries.