1. Atomic Structure Objectives 17 - 22

2. What is a Valence Electron Simple definition – the outermost electrons in an atom These are the last electrons added to an atom The last number in the electron arrangement listed on the Periodic Table of the Elements in your Reference Tables

3. What are ions? Any charged particle Positive ions and negative ions Can atoms gain or lose protons? Ever? So how do they change their charges ?

4. Names for ions Positive ions are called CATIONS Negative ions are called ANIONS When an atom becomes a positive ion its name doesn’t change When an atom becomes a negative ions its name changes to -ide

5. What they become Certain elements will make particular ions These are very predictable – they happen every time Groups 1,2,13-17

6. Writing electron arrangements for Ions All atoms are trying to end up with a full octet when they form ions Negative ions have more electrons than their neutral atom Positive ions have fewer electrons than their neutral atom

7. Examples Write the electron arrangement and the name for the following atoms and their usual ion counterpart –Na, Li, F, Mg, O, S, Al, C, Ca

8. Lewis Dot Diagrams Dots represent the Valence electrons only They do not show the Kernels One dot per valence electrons Arranged in a specific order around the imaginary box.

9. What do dot diagrams look like for ions? Some added details Dots represent its own electrons X’s represent electrons that came in from somewhere else You need to show the charge, negative or positive Negative ions need a bracket too.