Electron Configuration

Question

Give the condensed electron and orbital configuration, and indicate the valence electron for each of these elements:

a)Pt

b)U

c) I

Answer 1

For the condensed version, use the noble gas from the row above. Valence electrons are the electrons in the s and p orbitals, as those will have the highest energies (based on higher numbers in front of the letters). The order of orbitals is 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²4d¹⁰5p⁶6s²4f¹⁴5d¹⁰6p⁶7s²5f¹⁴7p⁶

a) Pt : [Xe]6s²4f¹⁴5d⁸, 2 valence

b) U : [Rn]7s²5f⁴, 2 valence

c) I : [Kr]5s²4d¹⁰5p⁵, 7 valence