Electronegativity/Electron Affinity (EN/EA): measure of how much an atom wants to gain an electron
EN/EA Left to Right across a Period: INCREASES (not including Noble Gases)
* Elements on the left side of the P.T. (metals) want to lose electrons. Elements on the right side of
the P.T. (nonmetals) want to gain electrons. Trend does not include Noble Gases because these
elements do not want to lose or gain electrons.
EN/EA Top to Bottom in a Group: DECREASES
This interference (and resulting decreased “hold”) is referred to as the SHIELDING EFFECT.
Ionization Energy (IE): amount of energy required to remove an atom’s most loosely held electron
IE Left to Right across a Period: INCREASES
* Elements on the left side of the P.T. (metals) want to lose electrons. Therefore, it will not require
much energy to remove an electron. Elements on the right side of the P.T. (nonmetals) want to gain
electrons. Consequently, a lot of energy will be needed to remove (take away) an electron.
IE Top to Bottom in a Group: DECREASES
Radius (AR): distance from the nucleus to the H.O.E.L.
AR Top to Bottom in a Group: INCREASES
* There are more occupied energy levels as you move towards the
bottom of the P.T.
AR Left to Right across a Period: DECREASES
how easily an atom will lose valence electrons (easier to lose = more
metallic = more reactive METAL)
Which metal loses its valence electron(s) most easily? Fr
* Francium has one valence electron. It is more reactive than elements at the top of Group 1 because there are many inner shell electrons that decrease the attraction the nucleus has for the valence electrons.
how easily an atom will gain electrons (easier to gain = more nonmetallic
= more reactive NONMETAL)
Which nonmetal gains electron(s) most easily? F
* Fluorine has seven valence electrons. It is more reactive than elements at the bottom of Group 17 because there are only a few inner shell electrons. Consequently, the nucleus has a strong attraction for other electrons.