Quantum Numbers and Electron Configurations

This video tutorial covers the concept of quantum numbers, which are essential for understanding the unique address of an electron within an atom. It explains the four types of quantum numbers: principal (n), angular momentum (l), magnetic (ml), and electron spin (ms). Each quantum number provides specific information about the electron's position and behavior. The video also includes practice problems to reinforce the understanding of these concepts, focusing on electron configurations and the relationships between different quantum numbers.

What does the principal quantum number (n) primarily describe?

• The shape of the orbital

• The energy level of an electron

• The spin of the electron

• The type of sublevel

Which sublevel corresponds to an angular momentum quantum number (l) of 2?

• p

• s

• d

• f

How many orbitals are there in a d sublevel?

• 7

• 1

• 5

• 3

What are the possible values for the electron spin quantum number (ms)?

• -1/2

• +1

• -1

• +1/2

How many unpaired electrons are in an atom of chromium?

• 8

• 6

• 4

• 2

Which of the following sub-levels does not exist?

• 3D

• 2p

• 5f

• 2D

What is the maximum number of electrons that can be found in the n=3 energy level?

• 8

• 10

• 18

• 32

Which element is paramagnetic?

• Magnesium

• Neon

• Krypton

• Phosphorus

What is the electron configuration for an element in the excited state?

• 1s2 2s2 2p6 3s1

• 1s2 2s2 2p4

• 1s2 2s1 2p3

• 1s2 2s2 2p6 3s2 3p6

Which group of elements corresponds to the configuration ns2 np4?

• Halogens

• Chalcogens

• Alkaline earth metals

• Alkali metals