Chapter 5.1 - Electrons and Bonding (electron structure)

Question 1

What are electron shells?

Answer 1

Electron shells are energy levels around an atom’s nucleus, used as a model to visualize the arrangement of electrons.

Question 2

How does energy relate to electron shells?

Answer 2

The energy of shells increases with their number, referred to as the principal quantum number n.

Question 3

What is the formula to calculate the maximum number of electrons in a shell?

Answer 3

Numberofelectrons=2n^2, where n is the shell number.

Question 4

How many electrons can the first four shells hold?

Answer 4

n = 1 –> 2 electrons
n = 2 –> 8 electrons
n = 3 –> 18 electrons
n = 4 –> 32 electrons

Question 5

What are atomic orbitals?

Answer 5

Atomic orbitals are regions around the nucleus where there is a high probability of finding electrons. Each orbital can hold up to two electrons with opposite spins.

Question 6

What are the different types of orbitals and their shapes?

Answer 6

s-orbitals: Spherical shape, one orbital per shell.

p-orbitals: Dumbbell shape, three orbitals per shell starting from n=2.

d-orbitals: Complex shapes, five orbitals per shell starting from n=3.

f-orbitals: More complex shapes, seven orbitals per shell starting from n=4.

Question 7

What is a subshell?

Answer 7

A subshell is a group of orbitals of the same type within a shell.

Question 8

How many orbitals are found in the s subshell?

Answer 8

1

Question 9

How many orbitals are found in the p subshell?

Answer 9

3

Question 10

How many orbitals are found in the d subshell?

Answer 10

5

Question 11

How many orbitals are found in the f subshell?

Answer 11

7

Question 12

What is the maximum number of electrons that can be found in the s subshell?

Answer 12

2

Question 13

What is the maximum number of electrons that can be found in the p subshell?

Answer 13

6

Question 14

What is the maximum number of electrons that can be found in the d subshell?

Answer 14

10

Question 15

What is the maximum number of electrons that can be found in the f subshell?

Answer 15

14

Question 16

What is the order of filling orbitals?

Answer 16

Orbitals fill in order of increasing energy:
1s,2s,2p,3s,3p,4s,3d,4p,5s,4d,5p,6s,4f,5d,6p.

Question 17

What is important to remember about the 4s and 3d filling and emptying order?

Answer 17

The 4s subshell fills before 3d, but 4s empties before 3d.

Question 18

Why do electrons pair with opposite spins?

Answer 18

Electrons are negatively charged and repel each other. Pairing with opposite spins minimizes repulsion within an orbital.

Question 19

What is the rule for filling orbitals within the same subshell?

Answer 19

Electrons occupy orbitals singly first to reduce repulsion, and pairing occurs only when no unoccupied orbital is available.

Question 20

What is electron configuration? Describe the electronic configuration of the example Krypton.

Answer 20

Electron configuration shows how electrons are distributed among an atom’s subshells. Example:
Kryton (Z=36): 1s^2,2s^2,2p^6,3s^2,3p^6,4s^2,3d^10,4p^6

Question 21

How is shorthand electron configuration written?

Answer 21

Shorthand uses the previous noble gas and outer subshells.

Question 22

Write the electronic configuration and the shorthand notation of Li.

Answer 22

1s^2,2s^1 –> [He]2s^1

Question 23

Write the electronic configuration and the shorthand notation of Na.

Answer 23

1s^2,2s^2,2p^6,3s^1 –> [Ne]3s^1

Question 24

Write the electronic configuration and the shorthand notation of K.

Answer 24

1s^2,2s^2,2p^6,3s^2,3p^6,4s^1 –> [Ar]4s^1

Question 25

How do ions affect electron configuration?

Answer 25

Positive ions (cations): Electrons are lost from the outermost shell.

Negative ions (anions): Electrons are added to the outermost shell.

Question 26

How is the periodic table divided based on electron configuration?

Answer 26

S-block –> left block of 2 groups
P-block –> right block of 6 groups
D-block –> centre block of 10 groups

Question 27

How are spins shown?

Answer 27

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