1. Periodic Table Trends

2. Arrangement of the elements in order of their atomic numbers so that elements with similar properties fall in the same column, or group What is it?

3. Group: vertical column of periodic table Period: horizontal row of periodic table Valence Electrons: electrons that occupy the highest energy level Up to 8 Atoms want to have full valence shell Ion: atom that has gained or lost an electron Cation: atom loses electron; has + charge Anion: atom gains electron: has - charge Important Terms

4. Silvery appearance Can be cut by knife Highly reactive with water Usually not found in nature as a pure element Always forms cations with +1 charge NOTE: Hydrogen, even though it is listed in group one, is NOT an alkali metal Alkali metals Group 1

5. Similar to alkali metals, but harder, denser, and stronger Also not usually found in nature as a pure element Always forms cations with +2 charge Alkaline-earth metals Group 2

6. Good conductors of electricity High luster Less reactive than alkali and alkaline-earth metals Some do not easily form compounds! Forms cations with varying charges Transition metals Groups 3-12

7. Most reactive non-metals React with metals to form salts Always form anions with -1 Charge Halogens Group 17

8. All electron shells full Little to no chemical reactivity Always has neutral charge Noble Gases Group 18

9. Do not easily fit in any particular group, so these elements are usually separated in it’s own area on the periodic table All actinides are radioactive Only 4 are found naturally Lanthanides and Actinides

10. Distance from the nucleus to the outer edge of electron cloud Increases as you go read down the group Decreases as you read across the period Why? Atomic radii Periodic Properties

11. Distance from the nucleus to the outer edge of electron cloud after an atom has gained or lost an electron Groups 1-13 form cations (+) Groups 15-17 form anions (-) Increase as you go read down the group Cationic radii decrease as you read across the period Anionic radii increase as you read across the period Why? Ionic radii Periodic Properties

12. The energy needed to remove an electron from an atom Decreases as you read down a group Increases as you read across a period Why? Ionization energy Periodic Properties

13. Energy change that occurs when an electron is gained by a neutral atom Represented as a negative number Decreases slightly as you read down a group Greatly increases as you read across a period Why? Electron Affinity Periodic Properties

14. The ability of an atom to attract an electron; only a property of atoms in compounds Decreases as you read down a group Increases as you read across a period Why? Electronegativity Periodic Properties