1. 1

2. Bonding Intra-molecular (are forces within a molecule, holding one atom to the next atom)

3. Three types of Intra bonding: 1. Ionic Bonding 2. Covalent Bonding 3. Metallic Bonding 3

4. 1. Ionic Bonding 4  Occurs between a metal & non-metal atom  Called ionic, because the atom must first become an ion  ion: a charged atom formed by the addition or removal of an electron from a neutral atom

5. Why do atoms form ions?  Valence!  The driving force behind chemistry is the favourable low-energy state atoms achieve by completing their valence shell  To fill their valence shells: a. metal atoms will lose e -, forming positive ions (cations) b. Non-metal atoms will gain e -, forming negative ions (anions) 5

6. Full Valence Shell  A full valence shell is considered to be 8 e- in the outer most shell  For smaller atoms like H, He, Li & Be, 2 e- is considered full  Atoms will gain or lose e- to achieve a full outer shell  The noble gases; He, Ne, Ar, Kr, Xe & Rn, already have a full shell Q: Are noble gases reactive or unreactive? A: Unreactive! They do not need to gain or lose e- so they are stable, (inert) 6

7. What holds ions together?  Opposite charges attract each other, just like a magnet  A cation, (+) will stick to an anion (-) creating an ionic bond  Opposites Attract - Paula Abdul Opposites Attract - Paula Abdul 7

8. Ionic Compounds are widely used; examples: Sodium Chloride  NaCl  Table salt  Road salt  NaCl is more readily available and does not have any special handling or storage requirements, unlike calcium chloride  More impact on environment, but less impactful on corrosion of vehicles Calcium Chloride  CaCl 2  Drying agent (desiccant packages)  Road salt  Calcium chloride is preferred over sodium chloride, as CaCl 2 releases energy upon forming a solution with water, heating any ice or snow it is in contact with  Less impact on environment, but promotes corrosion of vehicles 8

9. Examples: Sodium ChlorideCalcium Chloride 9

10. Formula & Naming 1 10

11. Formula & Naming 2 11

12. Polyatomic Ions 12  Some ionic compounds contain a charged molecule called a polyatomic ion  These ions are made of many atoms bonded together and sharing a charge over the whole molecule

13. Picture It: Ex: sulphate, (SO 4 ) 2-, o the polyatomic consists of 1 sulphur atom bonded to 4 oxygen atoms o the brackets tell us that whole molecule shares a charge of -2 o (meaning, overall there are 2 more e - than there are protons in this polyatomic) 13

14. 14 The brackets indicate an “electric fence”; you cannot touch anything inside because the whole thing is charged

15. 15 Example of a polyatomic compound: magnesium nitrate Mg(NO 3 ) 2 It is used in the ceramics, printing, chemical and fertilizer industries

16. Formula & Naming 3 16

17. 2. Covalent Bonding 17  Occurs between two non-metal atoms  Sometimes called a molecular bond  Non-metal atoms do not like to lose e -, but they still need a full outer shell to be happy;  therefore they share e - with adjacent atoms until each atom has a full valence shell

18. Transfer vs. Sharing Ionic BondCovalent Bond 18

19. Lewis Diagram (electron-dot)  As chemists, we are most interested in the valence e -  A Lewis diagram shows only the atom’s valence e -  The valence e - are the e - involved in bonding 19

20. Sharing not always equal Polar Non-polar  The difference in electronegativity between two atoms tells us about polarity; the bigger the difference the more polar the bond 20  With a difference of 1.4, the e - will spend more time with O, giving it a slight –ve and H a slight +ve  With a difference of 0.4, the e - will spend almost equal time with each atom

21. Naming covalent molecules  Some covalent molecules are called diatomic molecules; they do not get special names  H 2, O 2, F 2, Br 2, I 2, N 2, & Cl 2  Others follow a simple naming system:  Many more are known by their common names: H 2 O, NH 3 & CH 4  Water, ammonia & methane 21

22. 3. Metallic Bonding 22 a. Metal atoms exist in a uniform formation surrounded by a “ sea of electrons ”, because of this; b. they conduct electricity and c. heat and d. respond to force in a specific way