1. Ions Atoms that are not neutral

2. Atoms Are Neutral Let’s review: Why are atoms neutral? –Because they have equal numbers of protons and electrons. Li 3 7 Protons? 3 (same as atomic #) Neutrons? 4 (mass - atomic #) Electrons? 3 (same as # of protons)

3. -+ o + + o o o - - Why is this atom neutral? How many positive charges? 3 How many negative charges? 3 +3 + -3 = ? 0

4. Atoms can gain or lose electrons. Atoms are the most stable when their outer shells are full (like the Noble Gases).Atoms are the most stable when their outer shells are full (like the Noble Gases).- + o + + o o o - - What are two ways for Lithium to have a Noble Gas configuration? 1.Lose 1 electron 2.Gain 7 electrons --- ----

5. Which is easier? Is it easier for Lithium to LOSE 1 electron, or GAIN 7 electrons in order to have a full outermost shell?Is it easier for Lithium to LOSE 1 electron, or GAIN 7 electrons in order to have a full outermost shell? –Easier to LOSE 1 + o + + o o o - - - If Lithium LOSES 1 electron, is it neutral now? NO! How many protons? 3 How many electrons? 2 +3 + -2 = +1 Charged Ion

6. Let’s try another element… How about Beryllium?How about Beryllium? -- + o + + o o o - - + o - - --- - How can Beryllium achieve a Noble Gas configuration? LOSE 2 electrons GAIN 6 electrons Which is easier? LOSE 2! What is a Beryllium ion’s charge? +4 + -2 = +2 Charged ion

7. What about the other side of the periodic table? Let’s try Fluorine! - - - - - -- - + o + + o o o - - + o + + ++ + o o o o o o How can Fluorine achieve a Noble Gas configuration? LOSE 7 electrons GAIN 1 electron Which is easier? GAIN 1! What is a Fluorine ion’s charge? +9 + -10 = -1 Charged ion

8. A Neat Trick! To help you remember charges of ions of some elements (this trick does NOT work for transition metals).To help you remember charges of ions of some elements (this trick does NOT work for transition metals). -3+4 0 -1-2+2+3+1

9. Learning Check! See if you can use the new trick and the trick you learned before to predict # of valence electrons AND the ion charge for the following elements: 1.Calcium 2.Sodium 3.Chlorine 4.Oxygen 5.Carbon 6.Aluminum Valence ElectronsIon Charge 2 +2 1+1 7-1 6-2 4+/- 4 3+3

10. Ions have different names Cation-an ion with a positive charge. Easy way to remember: cation has a “t,” which looks like a + sign.

11. Anion-an ion with a negative charge. Easy way to remember: think “A N” for “a negative” ion. Ions have different names