CHM 143 Lecture Notes - Lecture 21: Effective Nuclear Charge, Atomic Radius, Unpaired Electron

• School: Oakland University
• Department: Chemistry
• Course: CHM 143
• Professor: Tillinger

Document Summary

Valence electrons: electrons that occupy orbitals in the outermost shells= highest principal quantum number. Increase energy electron with same principal quantum number= n. Main group elements= s and p subshells. Total number valence electron = x+y= group # in periodic table. Total # valence electrons = x+z= transition. Core electrons: all other electrons in an atom that are not valence electrons. #core electrons= #electrons(atomic # for atom)- valence electrons. Atomic radii: the radius of an atom. Trend (main group elements: period # increase = increase atomic radii (for same group, adding a shell, ex. K>na>li: group # increase= decrease atomic radii (for same period, zeff increase= greater pull on outer electron, ex mg(+2) vs p(+5) vs cl (+7) zeff, atomic radii mg>p>cl. The outermost shell ns2 is same for all. Pell off a layer of the onion. Zeff stays the same but # valence electrons increases. *increase # protons pulling same # electrons= pulls electrons in tighter smaller radius.