Atomic Structure

Question 1

Atomic/ Proton number (Z)

Answer 1

Number of protons in the nucleus

Question 2

Mass number (A)

Answer 2

Number of protons and neutrons in the nucleus

Question 3

What are isotopes?

Answer 3

Isotopes are atoms of the same element with the same atomic/ proton number (Z) but
different mass numbers (A), i.e. the same number of protons and electrons but different
numbers of neutrons.

Question 4

Formula for calculating Relative Atomic Mass (Ar)

Answer 4

Ar = ∑ (mass of each isotope x abundance of each isotope)

Question 5

What is the total abundance of all isotopes?

Answer 5

100%

Question 6

What are the four (4) quantum numbers?

Answer 6

n, l , ml & ms

Question 7

What is the Primal Quantum Number?

Answer 7

n

Question 8

What does the Primal Quantum Number indicate?

Answer 8

Energy of the shell
Size of the shell
The value of n also indicates the number of subshells present in the electron shell

Question 9

What does n usually take?

Answer 9

Positive Integer Values

Question 10

What is the Subsidiary Quantum Number?

Answer 10

l

Question 11

What does the Subsidiary Quantum Number Indicate?

Answer 11

This indicates the shape of the subshell

Question 12

What does l usually take?

Answer 12

l usually takes positive integer values from 0 to (n-1)

Question 13

What are the specific subshells of l?

Answer 13

0 = s subshell; 1 = p subshell; 2 = d subshell; 3 = f subshell

Question 14

What is the Magnetic Quantum Number?

Answer 14

ml

Question 15

What does the Magnetic Quantum Number Indicate?

Answer 15

This depicts the orientation in space of the orbital. Each value of l will have a distinct set of
values of m

Question 16

What does ml take?

Answer 16

ml usually takes integer values from –l to l, including 0

Question 17

What is the Spin Quantum Number?

Answer 17

ms

Question 18

What does the Spin Quantum Number Indicate?

Answer 18

It was postulated that electrons have an intrinsic property called electron spin that causes each
electron to behave as if it were a tiny magnet.
The values of ms refer to the direction/ orientation of spin of the electron (either ‘up’ or ‘down’)