This document defines and compares various periodic properties including atomic radii, ionization energy, electron affinity, ionic radii, valence electrons, and electronegativity. It states that atomic radii decreases left to right and increases down a group. Ionization energy generally increases across a period and decreases down a group. Electron affinity is the energy released or absorbed when an atom gains or loses an electron. Ionic radii are smaller for cations and larger for anions. Valence electrons are those involved in bonding and their number varies by main group element. Electronegativity generally increases across a period and decreases down a group.

1. Chapter 5.3 Electron Configurations and Periodic properties

2. Objectives: Define atomic radii and ionic radii, ionization energy, electron affinity, and electronegativity. Compare periodic trends for these properties and state reasons for variations. Define valence electrons, and state how many are present in atoms of each main-group element. Compare the these same properties of d-block elements with those of the main-group elements

4. Increase down a group

7. Generally decrease down a group

9. Forced

11. Formed by gain of one or more electrons

12. Larger due to addition of electron & remaining electrons are not pulled as strongly by nucleusIonic Radii

13. Valence Electrons Defined as the electrons available to be lost, gained, or shared in the formation of chemical compounds Valence electron Sodium atom Chlorine atom

14. Valence Electrons 1 2 3 4 5 6 7 8

16. Tend to increase across a period

17. Due to wanting to fill outer shell

18. Group trends