here
first of all that’s a bad question. Why? because the number of PROTONS determines which element you have. not the number of ELECTRONS. Ions are real, aren’t they?
and IF the atoms this question refers to are 1) neutral atoms, 2) have no higher energy level electrons THEN it would be strontium. How do you know?
One of two ways. you can count electrons like the other answerer did and say #protons = # electrons in a neutral atom and # = # atomic protons. then look for atomic #=38
Or you can familiarize yourself with the electron configuration by looking at the orbital guide in this periodic table.
http://www.ptable. with/
and move around and watch how the electrons fill up. the two columns on the left are the “s” electrons. the 6 columns on the right are “p”. middle is “d”… actinide and latanide are “f”
and for the “s” and “p” electrons, the line = # in front of the letter… 5S2 means 5th line. 2 electrons s. 5th row 2nd column… Strontium.
BUT everything I said…… Y (+1), Zr (+2), Ni (+3), Mo (+4), etc. also has this same electron configuration.
Total number of electrons = 2 + 2 + 6 + 2 + 6 + 2 + 10 + 6 + 2 = 38
This means that the atomic number is 38.
This implies that the element is strontium.
So the correct answer is:
D. M
Kr = 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 Mn = 1s2 2s2 2p6 3s2 3p6 4s2 3d5 or [Ar] 4s2 3d5 Bc = [Rn] 7s2 5f9 Zn= [Ar] 4s2 3d10 Zr = [Kr] 5s2 4d2 Dr = [Ar] 4s2 3d10 4p5 Sb = [Kr] 5s2 4d10 5p3 D = [Xe] 6s2 4f14 5d5