1. Day 14 – Covalent bonds Sci 10Chemistry

2. Covalent Bonds Non-metal + non-metal

3. A compound without any metals?!???! What happens when 2 nonmetals react? Remember: Metals want to give away their electrons and nonmetals want to accept them. A compound made of only nonmetals (Hydrogen counts as a non-metal) is called a covalent or molecular compound. Atoms in molecular compounds don’t want to lose their electrons SO … electrons are shared amoung multiple atoms to have full valence shells Animation: http://bcs.whfreeman.com/thelifewire/content/chp02/02020.html

4. H and Cl Hydrogen and chlorine are both gases and nonmetals (even though hydrogen is found in Group 1 (the alkali metals)). Neither H nor Cl want to give up their electrons to form an ionic sompound so they share them instead, forming a covalent bond (which gives us a covalent compound) H now has 2e - in its valence shell and Cl has 8, so they are both full. The line between H and Cl indicates there are 2e - shared between the 2 atoms. This form is called a Lewis Dot Diagram.

5. HOBrFINCl’s The following elements exist in a diatomic form (2 atoms are always bonded together). These diatomic molecules only exist in pairs of atoms. Draw Lewis Diagrams for H 2, O 2, Br 2, F 2, I 2, N 2 and Cl 2 Triple bond Double bond

6. Molecular compounds Give the structural formula (Lewis diagram with lines representing shared electrons) for the molecular compound that will form from the following pairs of elements: 1.bromine + iodine 2.nitrogen + chlorine 3.carbon + fluorine 4.sulfur + bromine

7. Answers Structural formula Br I Cl N Cl Cl F F C F F Br S Br

8. Practice Draw Lewis structures for the following compounds: H 2 O, CO 2, NH 3, SCl 2, CH 4, C 2 H 6, P 4, CBr 4, CH 2 Cl 2

9. P 4 et S 8 : Elemental shapes (Chem 11) No need to memorize this but just to show you that certain atoms bond to others forming specific angles. The compounds that are formed with have specific shapes.

10. Practice... again Show the bond formation between each of the following pairs of elements by drawing Lewis diagrams. Indicate if the compound formed is ionic or covalent. Try to write the formula for the compound. a)K and Sef)C and Cl b)Br and Clg)C and O c)Sr and Brh)N and I d)B and Hi) Ca and N e)Al and Sj)Al and Br

11. Naming Covalent Compounds 1.Is it a covalent compound (non-metal + non-metal)? If yes, 2.Name the element that is furthest left on the periodic table first. Use a prefix if there is more than one atom of this element. 3.Name the second element. Use a prefix to indicate the # of atoms (even if there is only 1) and add the ending –ide.

12. Prefixes # of atomsPrefix 1mono- (only use when naming the 2 nd element i.e. names of covalent compounds never start with mono-…) 2di- 3tri- 4tetra- 5penta- 6hexa- 7hepta- 8octa- 9nona- 10deca-

13. Examples and practice NO = nitrogen monoxide N 2 O = dinitrogen monoxide Name NO 2 –nitrogen dioxide Name CO –carbon monoxide

14. Try It! Name the following molecular compounds: 1.PI 3 phosphorus triiodide 2.SO 2 sulfur dioxide 3.SO 3 sulfur trioxide 4.S 2 F 10 disulfur decafluoride 5.CCl 4 carbon tetrachloride 6.N 2 O 5 dinitrogen pentoxide

15. Name to formula Look at the prefixes to write the formula Ex: phosphorus pentachloride PCl 5

16. Find the formula nitrogen tribromide –NBr 3 nitrogen dioxide –NO 2 sulfur pentoxide –SO 5

17. Naming diatomic molecules For the HOFBrINCl elements, they always exist in pairs of atoms as gases To name them, just use the name of the element – H 2 (g) = hydrogen – O 2 (g) = oxygen – N 2 (g) = nitrogen

18. To do Day 14 Covalent Practice