Beginning Chapter 8: Covalent Bonding -Today you will read Chapter When you are finished reading, complete the 8.1 study guide. Use the textbook to help you.

Exit Ticket 11/3/14 You are now on entrance ticket #5 We have begun chapter 8: Covalent bonding.. 1.) This is the dot structure for the molecule methane (CH 4 ). Draw it. Explain what you think it is showing.

Dot Structures for Molecules Dot Structures for Molecules 1.) Take your plain white piece of paper and fold it into 6 ths. Homework: finish dot structures

Entrance Ticket 11/5/14 1.) What is the purpose of drawing dot structures for molecules? 2.) Many of you put hydrogen peroxide (H 2 O 2 ) on your cuts and scrapes. It comes in a brown bottle and fizzes when you use it. What is its dot structure? Honors: on the school website I have posted a reading called “Lewis Dot Structures, Formal Charge and exceptions ”, read it tonight

Entrance Ticket 11/5/14 1.) What is the purpose of drawing dot structures for molecules? 2.) Many of you put hydrogen peroxide (H 2 O 2 ) on your cuts and scrapes. It comes in a brown bottle and fizzes when you use it. What is its dot structure? Homework: finish the first 8 dot structures

Entrance Ticket 11/6/14 You will need a pencil and an eraser today. 1.) Please draw the Lewis dot structure for the molecule carbon monoxide (CO). 2.) How many lone pairs are present? Honors: Read pg & do #23, 24 on pg. 236

Polyatomic Ions Poly: more than 1 Atomic: atoms Ion: has a charge Therefore, a polyatomic ion is a group of atoms that has a charge (has lost or gained electrons). Example: CO 3 2− (carbonate)

Entrance Ticket 11/7/14 1.) Read pages 237 to ) Answer # 32, 33, 34 from page 244.

Entrance Ticket 11/10/14 Read pages 237 to 241 (if you haven’t yet). 1.) What is a polar covalent bond and why does it happen? 2.) What is a dipole? 3.) Draw the dot structure for water (H 2 O) and show its dipoles.

Answers 1.) A polar covalent bond is when elements share electrons unequally thus forming dipoles. Polar bonds occur because a more electronegative atom pulls the electrons closer to it than the less electronegative atom. 2.) A dipole is the slight negative and slight positive sides of a molecule created from polar bonding.

Polar bonding between O & H

What type of bond? -You already know that when a metal and nonmetal bond, it’s ionic. When nonmetals bond it’s covalent. Let’s extend our knowledge using electronegativity… Using the notes page I gave you Friday, find the type of bond between these atoms: 1.) O and H5.) C and H 2.) Li and O6.) Ca and O 3.) Al and P7.) C and O 4.) S and C8.) B and Te

What type of bond? ANSWERS 1.) O and H: polar (3.5 – 2.1 = 1.4) 2.) Li and O: ionic (3.5 – 1.0 = 2.5) 3.) Al and P: polar(2.1 – 1.5 = 0.6) 4.) S and C: nonpolar (2.5 – 2.5 = 0) 5.) C and H: nonpolar (2.5 – 2.1 = 0.4) 6.) Ca and O: ionic (3.5 – 1.0 = 2.5) 7.) C and O: polar (3.5 – 2.5 = 1.0) 8.) B and Te: nonpolar (2.1 – 2.0 = 0.1) 9.) Si and Cl: polar (3.0 – 1.8 = 1.2)

Entrance Ticket 11/12/14 1.) Explain the difference between a polar and nonpolar covalent bond. 2.) Why is water a liquid at room temperature and not a gas? Make sure to study tonight! Quiz Tomorrow!

Answers 1.) In a polar covalent bond electrons are shared unequally. Nonpolar means the electrons are shared equally. 2.) Water has polar covalent bonds due to the higher electronegative oxygen. Since water is polar, water molecules are attracted to each other by hydrogen bonding.

More practice… 1.) Draw the dot structure for C 2 H 3 Cl. It is called chloroethene. 2.) Draw the Lewis dot structure for the polyatomic anion called phosphate (PO 4 3- ).

More practice… Which element in the 3 rd period likes to form 2 covalent bonds? Which element in the 4 th period likes to form 1 covalent bond? Which element in period 2 likes to form 4 covalent bonds?