how many electron pairs in 3rd energy level?its a challenge

Question

mathslover · Answer

in the third energy level there are maximum of 2n^2 = 18 electrons and 9 pair of electrons

anonymous · Answer

@mathslover is correct  :-)  

But there's an even easier way, what's the atomic (aka. # of protons) of the element on the last cell (right-hand side) on the 3rd row?   It's Argon, #18.  So how many protons does argon have?  18.   And how many electrons would it have if it was neutral (no ion charge)?  18 as well, has to.

Tip:  Learn to use the periodic table, and frankly I would recommend memorizing the first 3 or 4 rows (the atomic #'s and where that puts them on the table), as those are by far the most common elements encountered in chemical reactions.

mathslover · Answer

i think @agentx5 gave you a great tip and solution also .
best of luck