Bohr's Theory is based on an early model of atom where electrons travel round the nucleus in a discrete stable numbers of orbit determined by Quantum conditions. This is an extension of Rutherford Model of atom.

1. Bohr's Model of the Atom

2. Bohr's Model of the Atom
Niels Bohr (1913):

3. Bohr's Model of the Atom
Niels Bohr (1913):
-studied the light produced when atoms
were excited by heat or electricity

4. Bohr's Model of the Atom
Niels Bohr (1913):
-studied the light produced when atoms
were excited by heat or electricity

5. Bohr's Model of the Atom
Niels Bohr (1913):
-studied the light produced when atoms
were excited by heat or electricity
Rutherford's model couldn't explain why
unique colours were obtained by atoms of
different elements

6. Bohr's Model of the Atom
Niels Bohr (1913):
-studied the light produced when atoms
were excited by heat or electricity
Rutherford's model couldn't explain why
unique colours were obtained by atoms of
different elements
Bohr proposed that electrons are in orbits &
when excited jump to a higher orbit. When
they fall back to the original they give off light

7. Bohr's Model of the Atom
Bohr's model:
-electrons orbit the nucleus like planets
orbit the sun

8. Bohr's Model of the Atom
Bohr's model:
-electrons orbit the nucleus like planets
orbit the sun
-each orbit can hold a specific maximum
number of electrons

9. Bohr's Model of the Atom
Bohr's model:
-electrons orbit the nucleus like planets
orbit the sun
-each orbit can hold a specific maximum
number of electrons
orbit maximum #
electrons
1 2
2 8
3 8
4 18

10. Bohr's Model of the Atom
Bohr's model:
-electrons orbit the nucleus like planets
orbit the sun
-each orbit can hold a specific maximum
number of electrons
-electrons fill orbits closest to the nucleus
first.

11. Bohr's Model of the Atom
e.g. fluorine:
#P =
#e-
=
#N =

12. Bohr's Model of the Atom
e.g. fluorine:
#P = atomic #
= 9
#e-
=
#N =

13. Bohr's Model of the Atom
e.g. fluorine:
#P = 9
#e-
= # P
= 9
#N =

14. Bohr's Model of the Atom
e.g. fluorine:
#P = 9
#e-
= 9
#N = atomic mass - # P
= 10

15. Bohr's Model of the Atom
e.g. fluorine:
#P = 9
#e-
= 9
#N = 10
draw the nucleus with
protons & neutrons
9P
10N

16. Bohr's Model of the Atom
e.g. fluorine:
#P = 9
#e-
= 9
#N = 10
how many electrons can
fit in the first orbit?
9P
10N

17. Bohr's Model of the Atom
e.g. fluorine:
#P = 9
#e-
= 9
#N = 10
how many electrons can
fit in the first orbit?
2
9P
10N

18. Bohr's Model of the Atom
e.g. fluorine:
#P = 9
#e-
= 9
#N = 10
how many electrons are left?
9P
10N

19. Bohr's Model of the Atom
e.g. fluorine:
#P = 9
#e-
= 9
#N = 10
how many electrons are left? 7
9P
10N

20. Bohr's Model of the Atom
e.g. fluorine:
#P = 9
#e-
= 9
#N = 10
how many electrons are left? 7
how many electrons fit in the
second orbit?
9P
10N

21. Bohr's Model of the Atom
e.g. fluorine:
#P = 9
#e-
= 9
#N = 10
how many electrons are left? 7
how many electrons fit in the
second orbit? 8
9P
10N

22. Bohr's Model of the Atom
e.g. fluorine:
#P = 9
#e-
= 9
#N = 10
9P
10N

23. Bohr's Model of the Atom
try these:
hydrogen
boron
magnesium

24. Bohr's Model of the Atom
try these:
hydrogen
1P
0N

25. Bohr's Model of the Atom
try these:
boron
5P
6N

26. Bohr's Model of the Atom
try these:
magnesium
12P
12N