1.13 - Atomic orbitals and electronic configurations

Question 1

What are all electrons arranged in?

Answer 1

Quantum shells

Question 2

What do all electrons in the same quantum shell have?

Answer 2

Similar, but not identical, energies

Question 3

What do electrons in the first quantum shell have?

Answer 3

The lowest energy for that element

Question 4

What is each quantum shell divided into?

Answer 4

Sub shells

Question 5

What is the only subshell in the first quantum shell?

Answer 5

The 1s subshell

Question 6

What subshells does the second quantum shell contain?

Answer 6

The 2s and 2p subshells

Question 7

What subshells does the third quantum shell contain?

Answer 7

The 3s, 3p and 3d subshells

Question 8

What subshells does the fourth quantum shell contain?

Answer 8

The 4s, 4p, 4d and 4f subshells

Question 9

Order the following subshells in order of energy level, from lowest to highest:
1s
2s
2p
3s
3p
3d
4s

Answer 9

1s, 2s, 2p, 3s, 3p, 4s, 3d

Question 10

What does each subshells contain?

Answer 10

Orbitals

Question 11

What shape is an 1s orbital?

Answer 11

Spherical

Question 12

How many orbitals does the 2p subshell contain?

Answer 12

3

Question 13

What shape is each orbital in the 2p subshell?

Answer 13

An elongated dumbbell shape

Question 14

How many orbitals does the 3d subshell contain?

Answer 14

5

Question 15

How many electrons can an s subshell contain?

Answer 15

2 (1*2)

Question 16

How many electrons can a p subshell contain?

Answer 16

6 (3*2)

Question 17

How many electrons can a d subshell contain?

Answer 17

10 (5*2)

Question 18

How many electrons can an f subshell contain?

Answer 18

14 (7*2)

Question 19

What is the equation for finding the maximum amount of electrons in a quantum shell?

Answer 19

2n^2, where n is the number of the shell.

e.g. The second quantum shell can contain 2*2^2 = 8 electrons

Question 20

What is the notation for a subshell, for example the 2p subshell?

Answer 20

2p^n, where n is the number of electrons held within this subshell

Question 21

What is strange about the 3d and 4s subshells when it comes to electronic configuration of atoms that use these shells?

Answer 21

The 4s subshell has a slightly lower energy level than the 3d subshell, which means that it fills before the 3d subshell does

Question 22

What does Hund’s rule state?

Answer 22

That electrons will occupy the orbitals singly before pairing takes place

Question 23

What does The Pauli Exclusion Principle state?

Answer 23

That two electrons cannot occupy the same orbital unless they have opposite spins

Question 24

What is interesting about the electronic configuration of Chromium?

Answer 24

It is 1s^2 2s^2 2p^6 3s^2 3p^6 3d^5 4s^1

This is strange because the 3d and 4s subshells both half-filled, instead of the 4s subshell filling completely like we would expect. This is because having the 3d and 4s subshells half-filled is more stable than having the 4s subshell completely filled, and the 3d subshell with 4 electrons in it