Question

The number of valence electrons in an element with electron configuration 1s2 2s2 2p6 3s2 3p4 is ________.

Answer 1

The element is Sulfur, the sixteenth element of the periodic table.

The way I found out was by adding up the number of electrons listed.
Electron configuration can be shown by listing the orbital and then the number of electrons in the group.
1s is the innermost orbital and holds 2 electrons, so a full 1s is shown as "1s2"
Using this logic, I found that there were 2 + 2 + 6 + 2 + 4 = 16 electrons total.
Each element has an amount of electrons equal to the number of protons, AKA the element's atomic number.
As the element with the atomic number 16 is Sulfur, it is our answer.

Answer 2

Answer:

6

Explanation:

The given electron configuration 1s² 2s² 2p⁶ 3s² 3p⁴.

The valence shell of an atom is the outermost orbit. Here the valence shell is 3 with electrons occupying the  s and p orbitals.

The s orbital has 2 electrons and the 3p orbital has 6 electrons. So adding all the electrons in the 3s and 3p orbital we have a total of 6 electrons in the 3rd valence shell.