1. Periodic Trends Periodic law states that elements are arranged by their atomic numbers with similar properties occuring at regular intervals.

3. Definition: Half of the distance between nuclei in covalently bonded diatomic molecule  Radius decreases across a period  more p+ and e- for stronger magnetism.  Radius increases down a group  Each row on the periodic table adds a “shell” or energy level to the atom  Radius decreases across a period  more p+ and e- for stronger magnetism.  Radius increases down a group  Each row on the periodic table adds a “shell” or energy level to the atom Atomic Radius

4. Table of Atomic Radii

5. Period Trend: Atomic Radius

6.  Tends to increase across a period  As radius decreases across a period, the electron you are removing is closer to the nucleus and harder to remove  Tends to decrease down a group  Outer electrons are farther from the nucleus and easier to remove  Tends to increase across a period  As radius decreases across a period, the electron you are removing is closer to the nucleus and harder to remove  Tends to decrease down a group  Outer electrons are farther from the nucleus and easier to remove Ionization Energy Definition: the energy required to remove an electron from an atom

7. Periodic Trend: Ionization Energy

8. Electronegativity Definition: A measure of the ability of an atom in a chemical compound to attract electrons o Electronegativity tends to increase across a period o As radius decreases, electrons get closer to the bonding atom’s nucleus o Electronegativity tends to decrease down a group or remain the same o As radius increases, electrons are farther from the bonding atom’s nucleus o Electronegativity tends to increase across a period o As radius decreases, electrons get closer to the bonding atom’s nucleus o Electronegativity tends to decrease down a group or remain the same o As radius increases, electrons are farther from the bonding atom’s nucleus

9. Periodic Table of Electronegativities

10. Periodic Trend: Electronegativity

11. Electron Affinity Definition: the amount of energy released when an electron is added to a neutral atom or molecule in the gaseous state to form a negative ion. o Electron affinity tends to increase across a period o The closer to the nobel gases the closer to being happy. o Electron affinity tends to decrease down a group. If you add electrons as you go down you have more shells and it is farther away from the nucleus. o Electron affinity tends to increase across a period o The closer to the nobel gases the closer to being happy. o Electron affinity tends to decrease down a group. If you add electrons as you go down you have more shells and it is farther away from the nucleus.

12. Periodic Trend: Electron Affinity

13. Summary of Periodic Trends