Nwhich orbitals would the valence electrons for selenium (se) be placed?
s orbital and f orbital
s orbital only
s orbital and p orbital
d orbital only

The atomic number of selenium is 34. It is in the group 16.

The unit digit of the number of the group indicates the number of valence electrons. This is 6.

6 valence electrons means that it has 2 electrons in the s orbital and 4 electrons in the p orbital.

Then the answer is s orbital and p orbital.

You can verify this by searching the electron distribution, which is:

[Ar] 3d10 4s2 4p4

The six electrons in the highest energy level (4), 4s2 and 4 p4 are the valence electrons.