1. Atoms and the Periodic Table
14. nm
Chapter 17
Atoms and the Periodic Table

2. 14.3 nm
Chapter 17
Fe adsorbed on Cu
Section

3. Elements
The simplest form of matter that has a unique set of properties
Cannot be broken down into simpler substances chemical means

4. Elements
Pick elements
# of protons, electrons
Neutrons

5. The Periodic Table

6. 29 Cu
63.55

7. Why can’t you see individual atoms?
Smaller than the wavelengths of visible light
Use Scanning Tunneling Microscopy
400 nm

8. Scanning Tunneling Microscopy
STM Image Gallery

9. First Direct Evidence of Atoms
Robert Brown
1827
Grains of pollen in water under microscope
Brownian Motion

10. Parts of an Atom
1999 Science Joy Wagon

11. Atoms are mostly empty space
Electrostatic repulsion

12. Can you ever really touch the cat?
Not really!
Always a small gap between the atoms

13. Atomic Nucleus Particle Charge Mass compared to e- Mass (kg) Proton +1
1836
1.673 X 10-27
Neutron
1841
1.675 X 10-27
Electron -1 1
9.11 x 10-31

14. Nucleons
Particles in the nucleus
Protons
Neutrons

15. Mass Number
Mass Number= # protons + # neutrons

16. Isotopes
Atoms of an element that have different numbers of neutrons
1 2 𝐻

17. Nuclear Symbol
2 3 𝐻𝑒

18. Hyphen Notation
Name of Element – Mass Number
2 3 𝐻𝑒

19. Ions Protons – electrons = charge on ion Lithium 3 protons 4 neutrons

20. Ions
Chlorine
17 protons
18 neutrons
19 electrons

21. Isotope Activity