1. Line Spectra!

2. Periodic Trends Atomic Size/Atomic Radius

3. Atomic Radii Atomic radius = ½ the distance between adjacent nuclei (the next closest atom) In non-metals, it is ½ the distance between identical atoms that are bonded

4. Atomic Radii Trend Decreasing across the periodic table Increasing down the periodic table

5. Ionic Radius

6. Cations (+ charge) are always smaller than the neutral atom of the same element – Why? Because we are losing electrons! Anions (- charge) are always larger than the neutral atom of the same element – Why? Because we are gaining electrons!

7. Ionic radius Size decreases across the periodic table Size increases down the periodic table

8. Ionization Energy (IE) The energy required (in kJ/mole) to remove an electron from an atom Element A + energy  A + + electron

9. IE Decreases as you go down a group Increases as you go across the periodic table

10. Multiple Ionization Energies The energy required to remove the second (or more) electrons! Ex. Sodium (Na) (Element #11) IE 1  496 kJ/mole IE 2  4562 kJ/mole IE 3  6912 kj/mole