Atomic Structure

Question 1

Definition of Proton Number

Answer 1

The proton number (or atomic number) is the number of protons in the nucleus of an atom

Question 2

Definition of Nucleon Number

Answer 2

The nucleon number (or mass number) is the total number of protons and neutrons in the nucleus of an atom

Question 3

Definition of Isotopes

Answer 3

Isotopes are atoms of the same element having the same atomic number (same number of protons) but different nucleon number (due to different number of neutrons)

Question 4

First Ionisation Energy

Answer 4

The first ionisation energy of an element is the amount of energy required to remove one mole of electrons from one mole of gaseous atoms to form one mole of singly-charged gaseous cations.

Question 5

Second Ionisation Energy

Answer 5

The second ionisation energy of an element is the amount of energy required to remove one mole of electrons from one mole of singly-charged gaseous cations to form one mole of doubly charged gaseous cations

Question 6

Effective Nuclear Charge

Answer 6

Effective nuclear charge is a measure of the net attraction actually experienced by the outermost (valence) electrons