Each of the following electron configurations represents an atom in an excited state. What elements are these?

Question

1s22s22p63s13p1

1s22s22p63s23p44s1

1s22s22p63s23p64s23d44p1

Answer 1

1s22s22p63s13p1
12 electrons so Mg in an excited state (fundamental ...3s2)

1s22s22p6 3s23p4 4s1
17 electrons Chlorine (fundamental ...3p5)


1s22s22p6 3s23p64s23d4 4p1
25 electrons Mangnese (fundamental ...3d5)

Answer 2

It doesn't matter that they're in an excited state. Just count the total number of electrons. This gives you the atomic number. Consult a periodic table to get the element to which the atomic number corresponds.
1: 2 + 2 + 6 + 1 + 1 = 12. Carbon
2: 2 + 2 + 6 + 2 + 4 + 1 = 17. Chlorine
3: 2 + 2 + 6 + 2 + 6 + 2 + 4 + 1 = 25. Manganese