We went over how to make a formula based from a pair of Ions.
Ex. K+ and O2-
There are three ways to do this, Common Sense, Common Denominator and Criss-Cross.
Essentially, K+ and O2- will become K2O
REMINDER. PROTONS ALWAYS STAY THE SAME. THEY NEVER CHANGE.
We are always trying to pair up the ions so that they will be neutral.
If there are a group of ions and you need to choose which should go together, choose the two that will have opposite charges and will "cancel" each other out.
Ex. Na+ S2-, I-, Zn2+
Na+ and I- should go together because one ion has a +1 charge while the other has -1 charge. Their opposite charges will cancel each other out (which is our goal).
After we went over the homework/extra credit, we (as a class) did pages 6 and 7 together.
6 was also about forming ionic compounds, but 7 was about Polyatomic Ions.
- Ions made up of many atoms
- ex: NO3 -1
- There are many negative Polyatomic Ions bu only one positive Polyatomic Ion.
- NH4 +1
Polyatomic Ions are always written in a specific order. The positive part is written first and then the negative part is after.
Cation: Positive Ion. You can remember this by the t in cation. The t looks like a + for positive.
Anion: Negative Ion. You can remember this by the n in anion. N stands for negative.
Also, the new periodic tables that we metioned before have names of some polyatomic ions which is the updated part.
The homework was the rest of page 7 and page 8. For the homework, we haven't learned the names part yet, so that part doesn't need to be done. As always webassign is homework.
Have a good weekend and Happy Halloween!!