Atomic Number

1
Atomic Number

• Number of Protons

2
Mass Number

• Number of Protons Neutrons

3
C-12 or carbon-12

• 12 is the mass number.

4
12C

• Left Superscript mass number

6
5
12C

• Left Subscript atomic number

6
6
80Br

• 35

35
Atomic Number ?
7
20Ne

• 20

10
Mass Number ?
8
238U

• 238

92
Mass Number ?
9
27Al

• 27

13
Mass Number ?
10
40Ca

• 20

20
Atomic Number ?
11
19F

• 9

9
Atomic Number ?
12
U-235

• Mass Number 235
• Atomic Number 92 (Look up!)

Mass Number? Atomic Number?
13
C-14

• Mass Number 14
• Atomic Number 6 (Look up!)
• Number of neutrons 14 - 6 8

How many neutrons?
14
Isotope

• Atoms of the same element with a different of
  neutrons

15
Isotope

• Atoms with the same atomic but different mass

16
Characteristics of Proton

• Charge 1, mass 1 amu, location inside
  nucleus

17
Characteristics of Neutron

• Charge 0, mass 1 amu, location inside
  nucleus

18
Characteristics of Electron

• Charge -1, mass 1/1836 amu or 0.0005 amu,
  location outside nucleus

19
Ion

• An atom that has gained or lost electrons so
  carries charge

20
Nucleons

• Protons Neutrons

21
atom

• Smallest bit of an element that retains the
  properties of the element.

22
atom

• Electrically neutral.
• of protons of electrons.

23
Charge

• protons - electrons

24
of neutrons

• Mass number atomic number

25
14C

• 8

6
of neutrons ?
26
9Be

• 5

4
of neutrons ?
27
40Ar

• 22

18
of neutrons ?
28
15N

• 8

7
of neutrons ?
29
24Mg

• Right superscript charge

2
12
30
24Mg

• 10 electrons

2
12
of electrons?
31
86Rb

• 36 electrons

1
37
of electrons?
32
127Te

• 53 electrons

1-
52
of electrons?
33
32S

• 18 electrons

2-
16
of electrons?
34
20F

• 9 protons, 11 neutrons, 10 electrons

-
9
of protons, neutrons, electrons?
35
Cation

• Positive ion atom lost electrons

36
Anion

• Negative ion atom gained electrons

37
Avg. Atomic Mass

• Weighted avg. of masses of naturally occurring
  isotopes of an element.

38
2 isotopes of Cl 75 Cl-35 25
Cl-37.Calculate avg. atomic mass.

• Avg. atomic mass
• .75(35) .25(37) 35.5 amu

39
Daltons Model

• Billiard Ball Model

40
Thomsons Model

• Plum Pudding Model

-
-
-



-
-

41
Rutherfords Model

• Nuclear Model

-

-
-
42
Rutherfords Experiment
Source http//www.dlt.ncssm.edu/TIGER/chem1.htm
atomic
43
Rutherfords Experiment Results

1. Most of the alpha particles went straight
   through. ? Most of the atom is empty space.
2. Some of the alpha particles were deflected back.
   ? The nucleus was tiny, but contained most of
   the mass of the atom.

44
Bohrs Model

• Planetary Model

45
Schrodingers Model

• Modern or Quantum Mechanical Model

Source http//www.dlt.ncssm.edu/TIGER/chem1.htm
atomic
46
Modern Model (Schrodinger or Quantum Mechanical
Model)

• Electron treated as a wave.
• Never know exactly where it is.

47
Bohr Configuration

• Ground state configurations found in reference
  tables.
• Cannot be predicted.

48
Bohr Configuration of Na 2-8-1

• 2 electrons in energy level 1
• 8 electrons in energy level 2
• 1 electron in energy level 3

49
Bohr Diagram of Na
11
50
Valence Electron(s)

• Electron(s) in outermost orbit or shell

51
Kernel

• Nucleus all innershell electrons Everything
  except the valence electrons

52
Bohr Model

• Electrons are restricted to specific orbits or
  shells or principle energy levels.
• Each shell holds a specific of electrons.
• Each shell has a specific energy radius.
• Energy of electron must match energy of shell.

53
Maximum Capacity of Bohr Levels
Shell Max of electrons
1
2
3
4
n
2
8
18
32
2n2
54
Ground State

• Bohr model
• Every electron is in the lowest available orbit.

55
2-8-7

• Ground state configuration of Cl

56
2-6

• Ground state configuration of O

57
Ground state configuration of Kr?

• 2-8-18-8

58
Principle Energy Level?

• Shell

59
Excited State

• Bohr model
• An electron has absorbed heat, light, or
  electrical energy and moved to a higher energy
  level.
• Unstable. Returns to ground state quickly by
  emitting a photon.

60
2-5-1

• An excited state of O

61
2-0-1

• An excited state of Li

62
Continuous Spectrum

• Spectrum produced by holding a prism in sunlight.
  Contains light at every wavelength.
• Rainbow

63
Bright Line Spectrum

• Visible light produced by electrons in atom
  returning to ground state light of only a few
  wavelengths is present.
• Each element has a unique bright line spectrum.
  Used to identify elements.
• Wavelengths of bright lines correspond to
  difference between energy levels.

Source http//www.dlt.ncssm.edu/TIGER/chem1.htm
atomic
64
Absorbtion of Energy
Excited state
E3
E2
Ground state
h?
E1
65
Emission of Energy
Excited state
h?
E3
E2
Ground state
E1
66
Orbital

• Modern Model
• Region of space that holds 2 electrons.
• Has a specific energy. Shapes vary.

67
Represents an electron dropping to a lower energy
level, releasing energy in the process.
E2
E1