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 8 3 4 18

10. used to predict the reactivity of an element
Bohr's Model of the Atom
used to predict the reactivity of an element
Reactivity- how likely an element will form a compound with another element.
electrons fill orbits closest to the nucleus first. (later known as Aufbau principle)
Electrons in outermost orbit are called valence electrons, involved in chemical reactions

11. Drawing Bohr Models Draw the nucleus.
Write the number of neutrons and the number of protons in the nucleus.
Draw the first energy level.
Draw the electrons in the energy levels according to the rules below. Make sure you draw the electrons in pairs.
Draw the pairs as far apart from other pairs
Keep track of how many electrons are put in each level and the number of electrons left to use.

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

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

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

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

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

18. 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

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

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

22. 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

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

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

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

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

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