Week of 4-9-20

NOTE: ONLY USE THIS IF YOU CAN'T ACCESS GOOGLE CLASSROOM

9th Grade

·  Week 2:  Dot Structures and Determining Bond Types

QUICK REVIEW: Last week, you reviewed the number of protons, neutrons and electrons in an atom. Today we are focusing on the ELECTRONS

FIRST: Remember valence electrons are the electrons in the OUTERMOST level. These are the ones that participate in bonding, that is why we care about them. 

• RECALL: We look at the periodic table and the GROUP/FAMILY number tells us the amount of valence electrons, Group 1 has 1, Group 2 has 2, Group 13 has 3, Group 14 has 4.... Group 18 has 8.

You all remember, these are dot diagrams: 

 

SECOND: Now I need you to remember how we determine bond type using electronegativity (EN) values. 

Remember EN values tell us how much an atom is pulling/ taking the electrons…. F (values of 4) has a very strong pull, whereas Li (values of 1) does not have much of a pull or hold at all.

To determine the bond type between two atoms, we subtract the two EN values and use this table to figure out the bond “character” or the type of bond.

If we were looking at Li and F, 4-1= 3. So they would form an ionic bond with Li+ and F-

Remember, COVALENT bonds are sharing the electrons between the atoms. 

-Nonpolar Covalent is EQUAL sharing

- Polar Covalent is UNEQUAL sharing and we need to show PARTIAL CHARGES

ACTIVITY ON NEXT PAGE, SCROLL DOWN

ACTIVITY: 

Part 1.  For the following elements, create dot diagrams. Remember how we used fruit loops?? See how creative you can be and find something around your house to represent valence electrons and create dot diagrams, take pictures and attach. 

-If you can’t take pictures, describe WHAT you used and HOW MANY valence electrons you needed to add.

1. K
2. Mg
3. Br
4. Na
5. Si
6. Kr
7. N

Part 2.  For the following element combinations, CALCULATE using the EN values and determine the bond type.

Example: Hydrogen and Oxygen….

3.5-2.1= 1.4, this is POLAR COVALENT with partial negative on O and partial positive on H

8. Nitrogen and Oxygen
9. Lithium and Beryllium
10. Potassium and Bromine
11. Silicon and Silicon
12. Sulfur and Carbon

8th Grade

Week 2 Article 

Hi guys! Last week's assignment was a way to work out all the bugs. NEW DIRECTIONS FOR THIS WEEK! READ ON...

You are getting a new article this week. I attached a LINK.

https://newsela.com/read/human-connection-immune-system/id/2001007493

WHEN YOU ARE DONE READING create a document OR post in the private comments the answers to these questions:

1. Your answers to the multiple choice questions that are at the end of the article
2. One question you have about the article
3. One opinion or thought you have about the article