Question

Which of these have no unit?

• A. Electronegativity
• B. Electron affinity
• C. Ionisation energy
• D. Excitation potential

Answer 1

Answer: (A)

Electronegativity

Answer 2

The tendency of an atom to attract the bonding or shared pair of electrons towards its own side in a covalent bond is called electronegativity. It is a unitless quantity. Pauling scale and Mulliken scale are used to determine electro negativity. It increases in a period from left to right and decrease down a period. Fluorine is the most electronegative element of periodic table. ( $EN\approx 4.0$ according to pauling scale) Electron affinity and ionisation energy are expressed in $kJ/mol$ and electron volt / atom