Electron

1
Electron

• Named for elektron, an amber fossilized tree
  sap
• First discovered subatomic particles.

2
Thomson discovered the positively charged
particles we now call protons.
3
Thomsons Atom

• plum pudding model
• pudding charge
• raisins - charge

4
Nucleus

• core or center of the atom

5
Rutherfords Atom

• small central positive nucleus
• negative charges in empty space around nucleus.

6
Subatomic Particles
7
Subatomic Particles
8
Subatomic Particles
9
Subatomic Particles
10
Subatomic Particles
11
Atoms are identified by number of protons
12
Atoms are neutral

• Total protons total electrons

13
Atomic number

• the number of protons in an atom
• written just above the chemical symbol on the
  periodic table

14
Mass number

• the number of protons plus neutrons in an atom
• Commonly follows chemical symbol Ni-59

15
Review 1

• How many protons does C (carbon) have?

16
1

• How many protons does C (carbon) have?

six
17
Review 2

• How many electrons does C (carbon) have?

18
2

• How many electrons does C (carbon) have?

six
19
Review 3

• What changes did Thomson make to the atomic model
  of Daltons from about100 years earlier?

20
3

• Subatomic particles (protons electrons)
• Plum pudding model

21
Review 4

• What changes did Rutherford make to Thomsons
  atomic model?

22
4

• Atoms are mainly empty space
• Nucleus of protons neutrons
• Electrons in empty space around nucleus