[hsebast1]

y is it that cobalt has 9 valence electron and fe has 8..does this means that as u go further up u gained an extra valence electron,,,,

[BetaAmyloid]

The further you go (right) along a period the higher the number of valence electrons. However, Fe does not have 8 valence electrons and Co does not have 9 valence electrons. You are including the electrons in their d-orbitals. Valence are in the outermost electron shell, in this case, the s-orbital. D-orbitals always fall one behind s-orbitals and p-orbitals while f-orbitals always fall two behid s-orbitals and p-orbitals (and one behind d-orbitals) depending on if you have entered a period containing d-orbitals or f-orbitals.

Valence Electrons