The document describes the Bohr-Rutherford atomic model. It states that the atom consists of a small, dense nucleus containing protons and neutrons, surrounded by electrons in shells. The atomic number equals the number of protons, and a neutral atom has the same number of protons and electrons. Electrons are located in shells outside the nucleus, with the first shell holding 2 electrons and subsequent shells able to hold more. Diagrams illustrate atoms showing their arrangement of subatomic particles. Examples are provided of looking up atomic properties and drawing Bohr-Rutherford diagrams for different elements.

1. Bohr – Rutherford Atomic
Model
Objectives:
4.9 To describe the simplified atomic
model currently in use (Bohr-
Rutherford)

2.  Bohr & Rutherford combined their
theories to create the current
simplified atomic model
 The atom is made up of three sub-
atomic particles:
 Protons
 Electrons
 Neutrons
Bohr – Rutherford Atomic
Model:

3. The Atom:
Sub-Atomic
Particle
Charge Mass Location
Proton
Electron
Neutron
+
-
none
1 amu
negligible
1 amu
nucleus
outside
nucleus
nucleus

4. education.jlab.org/ qa/atom_model.html
The Atom:
nucleus
electron neutron
proton

5. Nucleus:
 Contains protons & neutrons
 Overall positive charge (+)
 Contains nearly all mass (dense)
Electrons:
 Located outside
nucleus
 Easily moved, lost
or gained
 Negative charge (-)

6.  Every atom has a symbol & two
numbers associated with it.
 Ex.
The Atom – Important Info:
C
12
6
Atomic Mass
Atomic Number
•The mass of an atom
•The bigger number
•The number of protons & neutrons
•The number of protons
•The smaller number
Since atoms are neutral,
the number of protons (+)
equals the number of electrons (-)

7. For the following atom, state the…
i) atomic mass
ii) atomic number
iii) # of protons
iv) # of electrons
v) # of neutrons
O
16
8
16
8
8
8
16 – 8 = 8

8. For the following atom, state the…
i) atomic mass
ii) atomic number
iii) # of protons
iv) # of electrons
v) # of neutrons
Na
23
11
23
11
11
11
23 – 11 = 12

9. For the following atom, state the…
i) atomic mass
ii) atomic number
iii) # of protons
iv) # of electrons
v) # of neutrons
Ar
40
18
40
18
18
18
40 – 18 = 22

10. Cu
64
29
64
29
29
29
64 – 29 = 35
For the following atom, state the…
i) atomic mass
ii) atomic number
iii) # of protons
iv) # of electrons
v) # of neutrons

11. For the following atom, which
statement is TRUE?
P 31
15
A) The atomic number is 31.
B) The atom has 15 neutrons.
C) The atom has 16 electrons.
D) The atom has 15 protons & 15 electrons.

12. Given a neutral atom, which statement
is TRUE?
A) An atom always has the same number of
electrons as neutrons.
B) Electrons & neutrons are found in the
nucleus.
C) The atomic number states the number of
neutrons.
D) An atom always has the same number of
electrons as protons.

13.  Atoms are made up of:
 Protons
 Electrons
 Neutrons
 Protons & Neutrons are located in
the nucleus
 Electrons are located outside the
nucleus

14.  An atom’s atomic number is equal to
the number of protons (smaller
number)
 An atom is neutral, therefore the
number of protons & electrons are
equal
 An atom’s atomic mass is equal to
the protons & neutrons together
(bigger number)

15. Activities:
 Physical Science Worksheet #7
Once you’ve
completed the
worksheet, continue
with the rest of the
lesson

16.  Recall, in the Bohr-Rutherford atomic
model, electrons are located outside
the nucleus
 Electrons are organized into:
 Electron shells or
 Energy levels or
 Orbitals
Electrons:
Be familiar with
all the terms,
especially the
first two

17.  Each electron shell differs in size &
the number of electrons it can hold
(capacity)
Electrons:
Electron
Shell
Capacity
1st 2 electrons
2nd 8 electrons
3rd 8 electrons*
4th 2 electrons*
Shows maximum #
of electrons in
each shell
Shells can be partially
filled or empty
*Simplified –
3rd shell holds 18 electrons
4th shell holds 32 electrons

18.  Is a picture of an atom, showing its
protons, electrons & neutrons.
 Ex.
Bohr – Rutherford Diagram:
Protons =
Electrons=
Neutrons=
3
3
4
3 P+
4 N0 2 e- 1 e-
Li
7
3

19. Draw a Bohr-Rutherford diagram for:
Protons =
Electrons=
Neutrons=
9
9
10
9 P+
10 N0 2 e- 7 e-
F
19
9

20. Draw a Bohr-Rutherford diagram for:
Protons =
Electrons=
Neutrons=
5
5
6
5 P+
6 N0 2 e- 3 e-
B
11
5

21. Draw a Bohr-Rutherford diagram for:
Protons =
Electrons=
Neutrons=
12
12
12
12 P+
12 N0 2 e- 8 e-
Mg
24
12
2 e-

22. Draw a Bohr-Rutherford diagram for:
Protons =
Electrons=
Neutrons=
19
19
20
19 P+
20 N0 2 e- 8 e-
K
39
19
8 e- 1 e-

23. Be9
4
Which of the following diagrams best
represents the Bohr-Rutherford model of…
A)
4 P+
5 N0
2 e-
3 e-
B)
5 P+
4 N0 2 e- 2 e-
C)
4 P+
5 N0
2 e- 2 e-

24. Draw a Bohr-Rutherford diagram for
each of the following atoms:
P
31
15
N
14
7
Al
27
13
15 P+
16 N0
2 e-
8 e-
5 e-
7 P+
7 N0
2 e-
5 e- 13 P+
14 N0
2 e-
8 e-
3 e-

25.  Electrons are located outside the
nucleus in electron shells
 In the…
 1st shell – 2 electrons
 2nd shell – 8 electrons
 3rd shell – 8 electrons*
 4th shell – 2 electrons*
 In Bohr-Rutherford diagrams:
 Place Protons & Neutrons in nucleus
 Place Electrons in appropriate shells
Find the
number of
Protons,
Electrons &
Neutrons

26. Activities:
 Physical Science Worksheet #8

27. References
 Student Study Guide – Physical
Science 416/436 - MEQ
 Science Quest – Grenier, Daigle,
Rheaume – 1998, Cheneliere
 Google Images
 Animation Factory