Question #179ac

2 Answers

Iodine would have a standard electron configuration of

1s22s22p63s23p64s23d104p65s24d105p5

The noble gas in the row above iodine is krypton.

We can replace 1s22s22p63s23p64s23d104p6 with the symbol [Kr] and rewrite the noble gas configuration of iodine as

[Kr]5s24d105p5

I hope this was helpful.
SMARTER TEACHER

Nov 21, 2014

The full electron structure of iodine is :

!s22s22p63s23p63d104s24p64d105s25p5

The noble gas Krypton has the electron configuration:

1s2222p63s23p63d104s24p6

We refer to this as the "Noble Gas Core" which we can write as :

[Kr]

So now we can write the electron configuration as :

[Kr]4d105s25p5

You will note that iodine has 7 valence electrons in the outermost n = 5 energy level, 4d being lower in energy than 5s. These electrons define the chemistry of iodine which can use some, or all of them in chemical reactions with oxidation states ranging from -1 to +7.