2. 1 st Ionization Energy The amount of energy required to remove an electron from an atom. Trend: Increases left to right across a row. Increases bottom to top of a column. Ex: Which of the following elements has the highest 1 st ionization energy? Na, Al, Cl, or Mg? Ex: Which of the following elements has the highest 1 st ionization energy? K, Rb, H, or Li?

3. Electronegativity The force with which a nucleus is attracted to its electrons How strongly an atom holds on to its electrons Trend Increases left to right across a row Increases bottom to top of a column. Ex: Which of the following elements has the highest electronegativity? Na, Al, Cl, or Mg? Ex: Which of the following elements has the highest electronegativity? K, Rb, H, or Li?

4. Atomic and ionic radius The size of an atom or ion (we’ll talk about ions later) Trend Increases right to left of a row Increases top to bottom of a column. Ex: Which of the following elements has the largest atomic radius? Na, Al, Cl, or Mg? Ex: Which of the following elements has the largest atomic radius? K, Rb, H, or Li?

5. Practice What is the name of column 1 on the periodic table? What is the name of column 17 on the periodic table? How many valence electrons do the noble gases have? Draw the lewis dot diagram for arsenic.