1. Drawing the Atom

2. Bohr’s model Electrons orbit the nucleus in “shells”
These shells have size limits and each shell can only have a certain amount of electrons in it.
Looks like the sun (nucleus) and planets (electrons)

3. Bohr - Rutherford diagrams
Putting all this together, we get Bohr diagrams
To draw them you must know the # of protons, neutrons, and electrons
Draw protons (p+), (n0) in circle (i.e. “nucleus”)
Draw electrons around in shells He Li
3 p+
4 n0
2e– 1e–
Li shorthand
3 p+
4 n0
2 p+
2 n0
Draw Be, B, Al and shorthand diagrams for O, Na

4. Be B Al O Na 8 p+ 11 p+ 8 n° 12 n° 4 p+ 5 n° 5 p+ 6 n° 13 p+ 14 n°
2e– 8e– 1e– Na
8 p+
8 n°
2e– 6e– O

5. Isotopes
Atoms of the same element that have different numbers of neutrons are called isotopes.
Li (6.9) is made up of both 6Li and 7Li.
Q- Draw Bohr diagrams for the two Li isotopes.
A- The atomic # of an element doesn’t change Although the number of neutrons can vary, atoms have definite numbers of protons.

6. 6Li 7Li
3 p+
3 n0
2e– 1e–
3 p+
4 n0
2e– 1e–