Question

All the following have the same electron configuration, EXCEPT: How do you solve this?

Ti 4+
Si 4-
Al3+
Sc 3+
Ar

Answer 1

I know the configurations, but none of them seal to be the same.

Answer 2

seem*

Answer 3

The answer is Al+3. If you notice, all of these elements are within 3 or 4 spaces to Ar. so we have Ti 4+, that means that we find Ti on the periodic table (row 4) and then we notice that it has a charge of 4+ meaning that we're taking away 4 electrons! If we take away 4 electrons then that is equivalent to moving 4 spaces to the left since Ti is now losing 4 valence shell electrons. Therefore by taking away 4 electrons, Ti now has the same electron configuration as Ar.
When you compare the others, you'll find a similar phenomena. The Si 4- is adding 4 electrons, so you move 4 places to the right and then we end up at Ar. The Sc 3+ takes away 3 electrons and also moves to the Ar electron configuration. All of them have this configuration except for Al3+ which has a Ne configuration.
Hope this helps :)

Answer 4

Excellent Answer

Answer 5

You're welcome =)