Definition

Question 1

Electronegativity (EN):

Answer 1

The electronegativity of an element is a measure of the ability of an atom to attract towards itself the electrons shared in a chemical bond.

Question 2

Atomic radius (AR):

Answer 2

The atomic radius of a metal is half the distance between the nuclei in two adjacent atoms”

Question 3

Ionic radius (IR):

Answer 3

The radii of an ion

Question 4

First Ionization energy:

Answer 4

The first ionisation energy is the energy required to remove the least tightly held electron from each atom in one mole of gaseous atoms in their ground state.

Question 5

Shielding

Answer 5

The repulsion of valence electrons by inner electrons.

Question 6

Standard enthalpy of combustion, ΔcH0

Answer 6

The standard enthalpy of combustion is the change in enthalpy per mole of a substance when it reacts completely with oxygen under standard conditions.

Question 7

Standard enthalpy of formation, ΔfH0

Answer 7

The standard enthalpy of formation is the standard reaction enthalpy for the formation of one mole of substance from its elements in their most stable form at standard state.

Question 8

The enthalpy of fusion, ΔfusH,

Answer 8

is defined as the enthalpy change that occurs when one mole of molecules changes from solid to liquid state.

Question 9

The enthalpy of vaporisation, ΔvapH,

Answer 9

is defined as the enthalpy change that occurs when one mole of molecules changes from liquid to gaseous state.