# Quiz - Quantum theory & Atomic structure | Quantum Theory and Atomic Structure

1

Which of the following sets of quantum numbers (n, l, ml) is not allowed?

(2, 1, 0)

(2, 0, 0)

(2, 1, -2)

(3, 2, -1)

(2, 1, -2) ⇒ n = 2; l = 0, 1; ml = -1, 0, 1 but -2 is not allowed

2

Which electrons are most likely to be involved in chemical reactions?

Those farthest from the nucleus

Those nearest to the nucleus

All are equally likely to be involved

The core electrons

Core electrons = electrons in inner energy levels = nearest to the nucleus = the most attracted by the nucleus = least likely to be involved in chemical reactions

3

What does the Pauli Exclusion Principle state?

It is impossible to determine accurately both the position and momentum of an electron simultaneously

2 electrons in the same atom cannot have the same set of 4 quantum numbers

2 atoms of the same element have the same number of protons

The ground state electron configuration is obtained by placing one electron in each orbital of the subshell with the highest energy

Pauli Exclusion Principle: 2 electrons in the same atom cannot have the same set of 4 quantum numbers (n, l, ml, ms)

4

What is the maximum number of electrons that can be accommodated in a sublevel for which l = 2?

6

8

10

14

l = 2 ⇒ d orbital

⇒ ml = -2, -1, 0, 1, 2 ⇒ 5 d orbitals ⇒ 10 electrons can be accommodated

5

What is the ground state electron configuration of nickel (Z=28)?

[Kr] 4s1 3d9

[Kr] 4s2 3d8

[Ar] 3d10

[Ar] 4s2 3d8

For the electron configuration, we can use an abbreviated form by using [previous nearest noble gas] for the valence electrons

6

How many unpaired electrons are there in the ground state of cobalt (Z=27)?

1

2

3

4 or +

Co (Z =27): [Ar]4s2 3d7

4s: 1 orbital filled with 2 electrons,

3d: 5 orbitals with 7 electrons ⇒ we place one electron in each orbital with parallel spin (5 electrons) then we add 1 electron in 2 orbitals with opposite spin ⇒ 3 electrons stay unpaired