1. Atomic Structure

2. ATOM Smallest unit of matter An element is made up of the same atom
ex: Gold (element on P.T) is made up of gold atoms

3. Parts of an Atom Atoms are made up of: Protons (p+): Positive charged
Electrons (e-) : negatively charged
Neutrons (no): no charge (neutral)
These are called subatomic particles

5. Nucleus is found in the centre of the atom
The two subatomic particles found in the
nucleus are _________________ and
______________
Shells (orbitals) are rings around the nucleus
___________________ are located in the shells outside the nucleus.
PROTONS
NEUTRONS
ELECTRONS

6. VALENCE SHELL VALENCE SHELL: outer most shell
Electrons found in the valence shell are called valence electrons

7. Determining number of protons, electrons and neutrons...
# protons = ATOMIC NUMBER # electrons = # protons (in a neutral atom) # neutrons = ATOMIC MASS – ATOMIC NUMBER

8. EXAMPLE: Oxygen
atomic number = 6 Atomic mass= # p= # e= # n= 6 6
16 – 6 = 10

9. Drawing Bohr-Rutherford Diagrams
Draw a circle representing the nucleus
Draw orbitals (dotted circles) around the nucleus
Hint: the period tells you how many orbitals to draw
In the nucleus, indicate how many protons (p+) and neutrons (n0)
Fill in the electrons on the orbitals
1st orbital: 2e-
2nd, 3rd, 4th, 5th, orbital – 8 e-

10. Let’s do an example!