1. COS 3.0, 3.1 CONTRAST THE FORMATION OF IONIC AND COVALENT BONDS BASED ON THE TRANSFER OR SHARING OF VALENCE ELECTRONS. DEMOSTRATE THE FORMATION OF POSITIVE AND NEGATIVE MONATOMIC IONS BY USING ELECTRON DOT DIAGRAMS.

2. WHAT YOU’LL LEARN Identify the number of valence electrons an element has based on its position on the periodic table. Construct electron dot diagrams (Lewis structures) based upon the number of valence electrons given for an element(s). Describe ionic & covalent bonds. Explain why some atoms transfer their valence electrons to form ionic bonds, while other atoms share valence electrons to form covalent bonds.

3. VALENCE ELECTRONS found in outermost shell of an atom determines atom’s chemical properties. So how do we know number of valence electrons an element has? based on their group on periodic table. REFER TO PERIODIC TABLE & LABEL

4. 1 ve 2 ve 3 ve 4 ve 5 ve 6 ve 7 ve 8 ve

5. Lets find some valence electrons. Si Xe K Ba I O Al P

6. OXIDATION NUMBERS AKA: charge change in oxidation number represents number of electrons gained or lost in a chemical reaction. REFER PERIODIC TABLE & LABEL

7. +1 +2 +3 +4+4 -3 -2

8. Lets find some oxidation numbers In F Rb Sn Ca N O

9. Lewis Structures AKA: electron-dot structures or electron-dot diagrams. Uses number of valence electrons. indicated by dots placed element’s symbol. diagram that shows bonding between atoms of a molecule. Always place element with largest number of valence electrons first, next largest … form ionic & covalent bonds

10. Lewis Symbols shows valence electrons as dots arranged around atomic symbol.

11. The Octet Rule Atoms tend to gain, lose, or share electrons until they have eight valence electrons.

12. Ionic Bonds TRANSFER of electrons from one bonding atom to another Occurs when electron transfers from a metal to a nonmetal

13. E l e c t r o n T r a n s f e r L i t h i u m Neon

14. Lewis Structures (Ionic) Draw Lewis structures for: HF: H 2 O: NH 3 : CH 4 : H F  H O H  H N H H  H C H H H 

15. COVALENT BONDING SHARING of electrons between two bonding atoms SHARING of electrons between two bonding atoms Occurs when electron shares between nonmetals Occurs when electron shares between nonmetals

16. Lewis Structures (Covalent) Draw Lewis structures for: KF: MgI: K F  Mg I ● ● ●●●● ● I ●●●● ● ●