I just have one more question regarding electron configurations for the following ions:

Question

Mo^3+

V^3+

I cannot understand why my answers are not working. Not listing as ground-state configs, but as full e- configs:

shouldn't Mo^3+ be:

1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d10, 4p6, 5s2, 4d1 (meaning: Mo^3+ = 39 valence electrons, rather than 42???)

&, for V^3+:

1s2, 2s2, 2p6, 3s2, 3p6, 4s2?? (meaning: V^3+ = 20 valence electrons, rather than 23???)

Answer 1

For V³⁺ you took the three electrons from the 3d. You should take both 4s electrons plus 1 of the 3d electrons. The 4s orbital is further out than the 3d. I know what you are thinking about filling and how you filled it but V³⁺ will have 3d2 and no 4s. Go to www.webelements.com and look at the electron configuration for Mo 3+ ion. I suspect something like the same kind of error.

Answer 2

I tried 1s2, 2s2, 2p6, 3s2, 3p6, 3d2 as well, it did not work either.

Answer 3

Then the answer machine is incorrect OR there is some form the answer is to be submitted and you aren't using that form. Have you tried [Ar]3d2?
Here is the site I gave you and you can see that 3d2 is correct. http://www.webelements.com/webelements/elements/text/V/key.html

Answer 4

Mo is [Kr]3d5 4s1.
Remove 1 s electron and 2 from 3d to leave
[Kr]3d3

Answer 5

I ran out of attempts. I am going to attempt to ask under the "help" to see what they say.

Answer 6

OK. Let me know.