Answer:
8 valence electrons
Step-by-step explanation:
We are given the atom has 10 electrons.
The first electron shell holds 2 electrons (maximum)
The second electron shell holds 8 electrons (maximum)
2+8=10
Therefore we would have 2 electrons in the first shell and 8 in the second.
Valence electrons are the outermost electron, and since the second shell is the outermost for the atom, it has 8 valence electrons.