Unit 2a: The Atom and Nuclear Chemistry
The Atom:
Atoms are the foundation of all matter, yet we still have much to discover and don't have a full understanding of how an atom works! In this first section, we will learn how the idea of the atom came to be and about the numerous scientists who helped shape our current understanding of the atom.
Subatomic Particles:
Sub= under or a part of. Subatomic means the tiny particles which make-up an atom. There are 3 main subatomic particles: protons, neutrons, and electrons.
Bohr Model:
Remember the Bohr model is also called the Planetary Model.
When drawing Bohr models we must first calculate the number of protons, neutrons, and electrons .
We'll use sodium-23 for an example:
p n e
+ o -
11 12 11
The protons and neutrons are in the nucleus. To show this we write the number of protons and neutrons in a center circle.
Then we must organize our electrons into energy levels.
1st energy level = 2 max electrons
2nd energy level = 8 max electrons
3rd energy level = 18 max electrons
11 12 11
p n e
+ o -
11 p
12 n
+
o
11 p
12 n
2e
-
Note: on any assessment (test or quiz) you MUST abbreviate the number of electrons by writing the number! NO DOTS!
+
o
8e
-
1e
-
Nuclear Chemistry:
Fission Vs Fusion:
