1. Day 4 – Reactivity & Ions Sci 10 Chemistry

2. Noble gases are the most popular group  A full valence shell contains happy electrons that want to stay where they are and are not very reactive (like the noble gases)  The octet rule: atomes react in order to have a full valence (outer) shell

3.  Group 1- Alkaline Metals  The most reactive metals  Group 2- Alkaline Earth Metals  Reactive but not as reactive as Group 1  Group 7 - Halogens  The most reactive non-metals  Groupe 8 – Noble Gases  Very unreactive. Stable because their valence shell is full

4. All atoms want to fill their valence shell To be stable and happy To be stable and happy  i.e. How can Na fill its valence shell?  Think of its Bohr-Rutherford diagram  It can either:  add 7 electrons (and be like Ar) OR  lose 1 electron (and be like Ne)  Which is easier???

6. Na cont’d  It will lose its only valence electron  The shell will no longer exist without an electron in it  Na will now have 10 electrons on 2 shells (like Ne)

7. All atoms want to fill their valence shell  i.e. How can F fill its valence shell? Think of its Bohr-Rutherford diagram  It can gain an electron to be like Ne OR it can lose 7 electrons to be like He

9. F cont’d  It will gain an electron to fill/ complete its valence shell  F will now have 10 e- (like Ne)

10. Ions  Ion: Atom or group of atoms that carries an electric charge  Cation – Positively-charged ion  formed when a neutral atom loses one or more electrons in order to have a filled valence shell  Ex : energy + Na  Na+ + electron 11 protons 11 protons 11 protons 11 protons -11 electrons - 10 electrons -11 electrons - 10 electrons 0 charge 1+ charge 0 charge 1+ charge **Remember: ditching something negative makes you more positive!

11.  Which groups form cations?  Group 1- Alkaline Metals  Lose 1 e- (to have a full valence shell) so they form cations with a charge of 1+.  i.e. : Na +  Group 2 – Alkaline Earth Metals  Lose 2 e- so they form cations with a charge of 2+  i.e.: Ca 2+ Almost all metals form cations

12. Ions  Anion – Negatively-charged ion  formed when a neutral atom gains one or more electrons in order to fill its valence shell  Ex : F + electron  F- + energy 9 protons 9 protons 9 protons 9 protons -9 electrons - 10 electrons -9 electrons - 10 electrons 0 charge 1- charge 0 charge 1- charge *Remember: getting more of something that is negative makes you more negative!

13.  Which groups form anions?  All non-metals  Group 7 - Halogens  gain 1 e- (to have a filled valence shell) so they form anions with a charge of 1-  i.e. : Cl + e-  Cl - + energy  Group 6  gain 2 e- so they form anions with a charge of 2-  i.e. : O 2–

14. Don’t forget…  Cations are positive: the “t” looks like the symbol “+”  Or: Cats have paws, cations are pawsitive  Or: Cats have paws, cations are pawsitive  Anions are negative

15. Naming Ions  Anion - (nonmetal) name ends in "ide" i.e. Chlorine atom forms a chloride ion  Cation - (metal) name is the regular name of the metal (no changes) i.e. Sodium atom forms a sodium ion

16. To do:  Day 4 Ions & Atoms Practice  Text p.109 #4, 9  Extra practice: Website – Keeping an Ion That Electron