1. Chapter 4 – 1 Atoms and the Periodic Table
Atomic Structure

2. What are atoms?
Democritus – universe made of invisible units called atoms
Atom – “unable to divide”
No real proof

3. Atomic Theory John Dalton – atoms cannot be divided
1800’s – English School Teacher
Atoms of a given element are alike
Atoms of different elements can form compounds

4. Parts of an Atom
Nucleus – central region that is made of protons and neutrons
Proton – subatomic particle
Positive Charge
In nucleus

5. Parts of an Atom Neutron – subatomic particle
No charge or neutral
Found in nucleus
Electron – subatomic particle
Negative charge
Found outside nucleus

6. Quarks
Protons and Neutrons are made of smaller particles called quarks.

9. No Charge Atoms are not charged Equal number of protons and neutrons
Charges cancel

11. Bohr’s Model Niles Bohr – electrons move in set paths around nucleus
Planets in the solar system
Electrons have a certain energy that determines its path

12. Bohr’s Model
Gain energy farther out
Lose energy closer in

14. Electron Location
Electron Cloud - Impossible to determine the exact location of an electron
Area where they most likely are

15. Electron Energy Level 1st level – 2 electrons 2nd level – 8 electrons
3rd level – 18 electrons
4th level – 32 electrons

19. Orbital
Orbital – region in atom where there is a high probability of finding electrons
Electrons occupy orbitals with lowest energy

20. Orbital 4 kinds of orbitals: s, p, d, and f S – sphere shape
Lowest energy
2 electrons

21. Orbital P – dumbbell shaped Orientated 3 ways in space
More energy that s
Each p holds 2 electrons
3 p = total of 6 electrons

23. Orbital D and F orbital – more complex D – 5 possible orientations
F – 7 possible orientations
Each hold a maximum of 2 electrons

25. Valence Electrons
Valence Electrons – found in the outermost shell of an atom
Determines chemical properties