1. Basic Chemistry Chapter 5 Electronic Structure and Periodic Trends
Chapter 5 Lecture
Basic Chemistry
Fifth Edition
Chapter 5 Electronic Structure and Periodic Trends
5.3 Sublevels and Orbitals
Learning Goal Describe the sublevels and orbitals for the electrons in an atom.

2. Energy Levels Energy levels
are assigned quantum numbers n = 1, 2,
increase in energy as the value of n increases.
have a maximum number of electrons equal to 2n2.

3. Number of Sublevels Energy levels
contain one or more sublevels identified by the letters s, p, d, and f.
contain a number of sublevels that is equal to the principal quantum number (n).

4. Order of increasing energy in sublevels in an energy level:
Sublevels and Energy
Within an energy level, the s sublevel is the lowest in energy, followed by the p, then the d, and finally the f.
Order of increasing energy in sublevels in an energy level:
s < p < d < f
Lowest Highest
energy energy

5. Learning Check
Identify the sublevels in each of the following energy levels.
A. n = 1
B. n = 4
C. n = 2

6. Solution
Identify the sublevels in each of the following energy levels.
A. n = 1 1s
B. n = 4 4s, 4p, 4d, 4f
C. n = 2 2s, 2p

7. Orbitals
An orbital
is a three-dimensional space around a nucleus where an electron has the highest probability of being found.
has a shape that represents its electron density (not a path the electron follows).

8. Shape of the s Orbital
Each type of orbital has a specific shape. In an s orbital, electrons are most likely found in a region with a spherical shape. There is one s orbital for every energy level; as the number of the energy level increases, the size of the spherical s orbital increases.

9. Shape of the p Orbitals
There are three p orbitals, starting with n = 2. Each p orbital has two lobes, like a balloon tied in the middle.
The p orbitals are arranged perpendicular to each other along the x, y, and z axes.

10. Energy Level n = 2
The second energy level, n = 2, contains two sublevels, 2s and 2p.
The 2s sublevel contains just one orbital with a spherical shape.
The 2p sublevel contains three p orbitals perpendicular to each other, 2px, 2py, and 2pz.

11. Energy Level n = 3
The third energy level, n = 3, contains three sublevels, 3s, 3p, and 3d.
The 3s sublevel contains just one orbital with a spherical shape.
The 3p sublevel contains three p orbitals perpendicular to each other, 3px, 3py, and 3pz.
The 3d sublevel contains five d orbitals:

12. Shape of the d Orbitals

13. Energy Level n = 4
The fourth energy level, n = 4, contains four sublevels, 4s, 4p, 4d, and 4f.
The 4s sublevel contains just one orbital with a spherical shape.
The 4p sublevel contains three p orbitals perpendicular to each other, 4px, 4py, and 4pz.
The 4d sublevel contains five d orbitals:
The 4f sublevel contains seven f orbitals, with complex shapes.

14. Learning Check
Indicate the type and number of orbitals in each of the following energy levels or sublevels.
A. 3p sublevel
B. n = 2
C. n = 3
D. 4d sublevel

15. Solution
Indicate the type and number of orbitals in each of the following energy levels or sublevels.
A. 3p sublevel three 3p orbitals
B. n = one 2s and three 2p orbitals
C. n = one 3s, three 3p, and five 3d orbitals
D. 4d sublevel five 4d orbitals

16. Orbital Capacity and Spin
The Pauli exclusion principle states that each orbital can hold a maximum of two electrons. An electron is seen as spinning on its axis and generates a magnetic field.

17. Orbital Capacity and Spin
Electrons in the same orbital have opposite spins, and therefore their magnetic fields cancel. We use arrows to represent electron spin.

18. Number of Electrons in Sublevels
There is a maximum number of electrons that can occupy each sublevel.
An s sublevel can hold one or two electrons.
Because each p orbital can hold two electrons, the three p orbitals in a p sublevel can hold a maximum of six electrons.

19. Number of Electrons in Sublevels
A d sublevel with five d orbitals can hold a maximum of 10 electrons.
An f sublevel with seven f orbitals can hold a maximum of 14 electrons.

20. Electron Capacity in Sublevels

21. Learning Check
What is the number of A. electrons that can occupy a p orbital? (1) 1 (2) 2 (3) 3 B. p orbitals in the 2p sublevel? C. d orbitals in the n = 4 energy level? (1) 1 (2) 3 (3) 5

22. Learning Check
What is the number of A. electrons that can occupy a p orbital? (2) 2 B. p orbitals in the 2p sublevel? (3) 3 C. d orbitals in the n = 4 energy level? (3) 5