Quantum Mechanics

Electron configuration of copper atom is 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s¹. Determine the number of electrons in copper atom at its ground state if the azimuthal quantum number, l, is 0.

• 9

• 7

• 6

• 10

Which of the following represents an electron in 3p orbital?

• n = 3, l = 0, m = +1, s = + ½

• n = 3, l = 2, m = +2, s = + ½

• n = 3, l = 1, m = +1, s = + ½ 

• n = 3, l = 0, m = 0, s = + ½

Answer explanation

electron in 3p orbital means the value of n must be 3 and the value of l is 1

1. Given the following sets of quantum number for n, l, m, s which of the set is NOT possible for an electron in an atom?

• n = 5, l = 2, m = -2, s = + ½

• n = 3, l = 2, m = +2, s = - ½

• n = 4, l = 4, m = -3, s = + ½

• n = 3, l = 1, m = -1, s = - ½

Answer explanation

When n=4, l = <4 (the value of  l can range from 0 to n-1)

The quantum number that determines the shape of an orbital is

• m

• s

• n

• l

Answer explanation

n  :principal quantum number (determine general energy level)

l   : azimuthal quantum number (determine shape of an orbital)

m : magnitude quantum number (determine the orientation of orbitals)

s  : electron spin quantum number (determine electron spin)

A possible set of quantum numbers for an electron in the 3d orbital is

• n=3, l=2, m=-1, s=1/2
• n=2, l=1, m=0, s=1/2
• n=3, l=1, m=1, s=1/2
• n=4, l=2, m=0, s=1/2

Answer explanation

electron in 3d orbital means the value of n must be 3 and the value of l is 2

For an electron that has quantum numbers n = 3 and l = 2, which of the following is true?

• 3. The electron may have the magnetic quantum number m = +3

• 1. The electron is in 3d orbital

• The electron has a electron spin quantum number s = 2

• The electron is in the 2nd energy level

When considering the quantum numbers for a p orbital, which of the following is true?

• 1. magnetic quantum number MUST be 2

• 1. principal quantum number MUST be 1

• angular momentum quantum number MUST be 1

• electron spin quantum number MUST be 1

Which of the following sets of quantum numbers is not allowed?

• 1. n = 2, l = l, m = 0, s = + 1/2

• 1. n = 3, l = 0, m = 0, s = + 1/2

• 1. n = 3, l = 1, m = -2, s = + 1/2

• n = 2, l = 1, m = -1, s = - 1/2

Give the corresponding atomic orbital designations for electrons with the following quantum numbers.

• 3d, 2p, 4f

• 3p, 2s, 4f

• 3p, 2p, 4f

• 3d, 2s, 4d

Choose the correct statement(s) about 4f orbital

I. The magnetic quantum numbers are -3, -2, -1, 0, 1, 2, 3.

II. The principal quantum number is 4 and the azimuthal quantum number is 3.

III.A maximum of 14 electrons can be filled in the orbital.

• I only

• I and II only

• II and III only

• I, II and III