October 25

Today in class we worked on getting caught up with homework in anticipation of Progress report which are coming out on November 9.

You did have a quiz at the end of class on Isotopes.

No Homework this weekend. Get caught up if you are missing work.

October 23

Hi Class,
We began class today with a Quiz on Physical and Chemical Changes and Properties.


In today's lecture, we covered Unit 2 Section A.8.
Topics:
Mass number
Isotopes

Remember:
Every element has a unique number of protons, that DOES NOT CHANGE. If I change the number of protons, the element is not the same. For example an atom of Sodium always has 11 protons. If I have an atom with 10 protons, I have Neon, NOT an ion of Sodium.

Number of Protons are given by the Atomic Number

In a Neutral atom, protons are equal to electrons

Every element can have atoms with varying numbers of Neutrons. For example you could have 3 atoms of Carbon:

6 Protons, 6 Neutrons, 6 Electrons
6 Protons, 7 Neutrons, 6 Electrons
6 Protons, 8 Neutrons, 6 Electrons

All three have the same numbers of Protons (Atoms of the same element have the same number of Protons). But the number of Neutrons have changed. These are Isotopes.

If I add the Neutrons and Protons, I get the Mass Number for that Isotope.

Homework:
Page 131 #19-21
Worksheet
Hint: Atomic Number equals Protons
Protons equals Electrons
Mass Number = Protons + Neutrons

You will have a quiz next class, similar to this worksheet.

October 19

Today in class we started Unit 2A

Here is the Power Point:

http://www.scribd.com/doc/407989/Unit2SectionA-oct-19

Homework this weekend:
Page 130-131 #1-5, 7-15

Have a great weekend.

October 11

Today you took your Mid Unit 1C retest. Remember your grade for the test and retest will be averaged together. The result will be recorded as your grade on the test.

Homework: None

October 8

Today in class we reviewed our last test in preparation for retest on Wed.

Homework:
Study material for retest