Lesson Worksheet: Quantum Numbers Chemistry

In this worksheet, we will practice using quantum numbers to describe an electron within an atom.

Q1:

The quantum numbers for three electrons in an atom of silicon are shown. What is the correct order from lowest to highest energy of these electrons?

  1. 𝑛=2,𝑙=1,𝑚=+1,𝑚=12
  2. 𝑛=3,𝑙=1,𝑚=1,𝑚=12
  3. 𝑛=2,𝑙=0,𝑚=0,𝑚=+12
  • A3, 1, 2
  • B2, 3, 1
  • C2, 1, 3
  • D1, 2, 3
  • E3, 2, 1

Q2:

Which of these sets of four quantum numbers does not exist?

  • A𝑛=2, 𝑙=2, 𝑚=0, 𝑚=+12
  • B𝑛=3, 𝑙=2, 𝑚=1, 𝑚=+12
  • C𝑛=1, 𝑙=0, 𝑚=0, 𝑚=+12
  • D𝑛=4, 𝑙=3, 𝑚=2, 𝑚=+12

Q3:

If 𝑛=1, how many possible values of 𝑙 are there?

Q4:

How many electrons in total can have the quantum numbers 𝑛=2 and 𝑙=1?

Q5:

The quantum numbers for the valence electron in an atom of lithium are 𝑛=2, 𝑙=0, 𝑚=0, and 𝑚=+12. What are the quantum numbers for the second valence electron in an atom of beryllium?

  • A𝑛=2, 𝑙=1, 𝑚=0, and 𝑚=12
  • B𝑛=3, 𝑙=0, 𝑚=0, and 𝑚=+12
  • C𝑛=2, 𝑙=0, 𝑚=0, and 𝑚=12
  • D𝑛=2, 𝑙=0, 𝑚=1, and 𝑚=+12
  • E𝑛=3, 𝑙=0, 𝑚=0, and 𝑚=12

Q6:

If 𝑙=0, how many possible values of 𝑚 are there?

Q7:

How many electrons can have a principal quantum number (𝑛) equal to 1?

Q8:

What is the relationship between the principal quantum number, 𝑛, and the total number of orbitals?

  • A𝑛
  • B𝑛2
  • C𝑛
  • D2𝑛
  • E2𝑛+1

Q9:

Two electrons, A and B, have the same energy. Electron A has the quantum numbers 𝑛=4,𝑙=3,𝑚=+1, 𝑚=+12. What are the quantum numbers of the electron B, knowing that it spins in the opposite direction?

  • A𝑛=4,𝑙=3,𝑚=+1,𝑚=+12
  • B𝑛=3,𝑙=2,𝑚=+1,𝑚=+12
  • C𝑛=4,𝑙=3,𝑚=+1,𝑚=12
  • D𝑛=3,𝑙=2,𝑚=+1,𝑚=12

Q10:

Which of the following is correct when two electrons of an atom have the same 𝑙 and 𝑚 values?

  • AThey must be located in the same energy level.
  • BThey can not have the same 𝑚 and 𝑛 values at the same time.
  • CThey are not located in the same energy sublevel.
  • DThey must have the same spin direction.

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