Question

Identify the period and group numbers of the element with the electron configuration. [Ne]3s23p4

Answer 1

It partially fills 3p meaning it's in the 3rd period; it completes 3s (hence 3s2) and fills 4 electrons of 3p (hence 3p4) meaning it's in group 2 + 4 = 6.

Answer 2

Another way to answer the question is to look at the periodic table:
http://en.wikipedia.org/wiki/Periodic_table

Then all you have to do is find Neon (Ne) and count across as the shells fill up: "s is full so you can go past Na and Mg, then count four more elements across and you'll come to the correct one.