ppt

1. Chapter 5
Quantum Numbers
Part 1

2. Quantum Numbers
• There are four
quantum numbers
that describe the
properties of an
electron and the
“orbital” that it
occupies within an
atom.
Apple

3. What are orbitals?
• The main division of energy for an electron
within an atom is called the energy level or
shell.
• The energy level (shell) is subdivided into
distinct areas called sublevels (subshells).
• The sublevels are divided into orbitals. The
orbitals are where the electrons are found.
• Each orbital can hold no more than a pair of
electrons.

4. Four Quantum Numbers
describe the following:
1. distance from the nucleus
2. shape of the orbital
3. 3-dimensional positioning of the orbital
4. direction of electron’s spin within the
orbital

5. The First Quantum Number
The Principal Quantum Number
• Abbreviated as “n”
• n = 1,2,3...
• Represents the
distance of an
electron from the
nucleus & the main
energy level of the
electron.

6. What else does the Principal
Quantum Number (n) tell us?
• n = number of
sublevels in the
energy level.

7. What else does the Principal
Quantum Number (n) tell us?
• n2 = number of
orbitals in the
energy level.

8. What else does the Principal
Quantum Number (n) tell us?
• 2n2 = maximum
number of electrons
possible in the
energy level.

9. n Energy
level
# of
sublevels
# of
orbitals
Max # of
electrons
1 1 1 1 2
2 2 2 4 8
3 3 3 9 18
4 4 4 16 32

10. The Second Quantum Number
(Types of Sublevels)
• The second quantum number identifies the
type of sublevel that the electron occupies.
• There are four types of sublevels in atoms.
• The sublevels are identified by the letters:
s, p, d, f

11. “s” sublevel and “p” sublevel
p orbitals have a
dumbbell shape
a s orbitals have a
spherical shape

12. Types of sublevels
• There are four types of sublevels in atoms.
• The sublevels are designated s, p, d, f.
n Energy
level
# of
sublevels
Sublevel
types
1 1 1 1s
2 2 2 2s, 2p
3 3 3 3s, 3p, 3d
4 4 4 4s, 4p, 4d, 4f

13. The Third Quantum Number
• The third quantum number identifies the
orbital that the electron is in.
• An orbital is an area within a sublevel that
can hold up to two electrons.

14. An “s” sublevel has one orbital

15. A “p” sublevel has three orbitals

16. A “d” sublevel has five orbitals

17. An “f” sublevel has seven orbitals

18. The 4th Energy Level
• n = ?

19. The 4th Energy Level
• n = 4

20. The 4th Energy Level
• How many sublevels are present and
what type are they?
• Four sublevels: s, p, d, f

21. The 4th Energy Level
• How many orbitals are present?
• n2 = (4)2 = 16

22. The 4th Energy Level
•What is the maximum number of electrons?
•2n2 = 2(4)2 = 32

23. The Fourth Quantum Number “s”
• Also called the spin quantum number.
• Can be either +1/2 or -1/2.
• Specifies the direction of spin of the
electron on its axis.
• Spins are designated up or down.

24. Electron Spin
• Opposite spins
produce opposite
magnetic fields.
+1/2 -1/2

25. What sublevel is the first to
be filled with electrons?
O

26. Which sublevel listed
contains orbitals of the
highest energy?
O

27. Finish Video
• Electron Arrangement and Bonding.

28. Homework
• Complete Chapter 5 Worksheet 1