How many valence electrons will an atom of iron atomic number 26 have? explain why this is.

If atomic number is 26 than electronic configuration would be 1s2s2p3s3p3d

there are two electrons in 1s

two electrons in 2s

six electrons in 2p

two electrons in 3s

six electrons in 3p

eight electrons in 3d

valence electron is 3 so 3s3p3d = 2+6+8

=16 electrons in valence shell