What element has the electron configuration 1s22s22p63s23p2?

The electron configuration #1s^2 2s^2 2p^6 3s^2 3p^2# is the element Silicon.

The key to deciphering this is to look at the last bit of information of the electron configuration #3p^2#.

The '3' informs us that the element is in the 3rd Energy Level or row of the periodic table. The 'p' tells us that the element is found in the p-block which are all of the Groups to the right of the transition metals, columns 13-18. The superscript '2' tells us that the element is found in the 2nd column of the p-block Group 14.

I hope this was helpful.
SMARTERTEACHER