Quantum Numbers Flashcards
n
- Principal quantum number
- Integer
- Describes the energy level of an electron inside an atom
ℓ
- Angular momentum quantum number
- 4 different sublevels: s, p, d, f
- For the s sublevel, ℓ is 0, for p, ℓ is 1, for d, ℓ is 2, and for f, ℓ is 3
What is ℓ for the s sublevel?
0
What is ℓ for the p sublevel?
1
What is ℓ for the 2 sublevel?
2
What is ℓ for the f sublevel?
3
Describe the relationship between n and ℓ
ℓ ≤ n-1
So when n=2, ℓ=0 or 1
When n=1, what is ℓ?
ℓ=0 (s)
When n=2, what are the possible values of ℓ?
ℓ=0, 1 (s,p)
When n=3, what are the possible values of ℓ?
ℓ=0, 1, 2 (s,p,d)
When n=4, what are the possible values of ℓ?
ℓ=0, 1, 2, 3 (s,p,d,f)
mℓ
- Magnetic quantum number
- Describes the orbital within a sublevel
-ℓ ≤ ml ≤ ℓ
e.g. if ℓ=4, -4≤ ml ≤ 4
When ℓ=0, what is mℓ?
0
When ℓ=1, what are the possible values of mℓ?
-1, 0, 1
When ℓ=2, what are the possible values of mℓ?
-2, -1, 0, 1, 2
When ℓ=3, what are the possible values of mℓ?
-3, -2, -1, 0, 1, 2, 3
ms
- Electron spin number
- ms = ± 1/2
↑ spin is +1/2, ↓ spin is -1/2
What are the four quantum numbers of 3d8?
How many electrons can each orbital hold?
2
How many electrons in an atom can have the quantum numbers n=5, ℓ=2?
Since there are 5 orbitals and each orbital can hold 2 electrons, 5x2 = 10 electrons
True or false: two electrons can simultaneously occupy the same (n, ℓ, mℓ) orbital
True, as long as their ms (spin) quantum numbers are not the same
How many quantum numbers are needed to describe an orbital?
3: n, ℓ, mℓ
How many quantum numbers are needed to describe an electron?
4: n, ℓ, mℓ, ms
A single electron in an orbital has quantum numbers n = 2, ℓ = 0, mℓ = 0, ms = +½.
What are the quantum numbers for the next electron added to this atom?
n = 2, ℓ = 0, mℓ = 0, ms = -½
For ℓ=1 (p orbitals), m=0 is the __ orbital and m=±1 are the __ and __ orbitals
m = 0 is the pz orbital m=±1are the px and py orbitals
How many electrons in an atom could have the quantum number n=3?
18
When n=3, it represents the third energy level, which includes the 3s, 3p, and 3d subshells. Each subshell can hold 2 electrons, so the total is 2 (for 3s) + 6 (for 3p) + 10 (for 3d) = 18 electrons.
What does it mean if two orbitals are degenerate?
Same n&ℓ, same energy level
When ℓ=3, how many degenerate orbitals are possible?
7: -3, -2, -1, 0, 1, 2, 3
The number of degenerate orbitals is equal to the number of mℓs
