Question

Outlibe 2 reasons why electronegativity increases across period 3 and one reason why the noble gases are not assigned electronegativity values

Answer 1

$\huge \bold{ANSWER}$

THE MODERN PERIODIC TABLE

The modern periodic table is an arrangement of elements in increasing order to their atomic numbers is based on modern periodic law "PROPERTIES OF ELEMENTS ARE PERIODIC FUNCTION OF THEIR ATOMIC NUMBER ".

PERIODIC PROPERTIES :--

Occurrence of characteristics properties of elements at definite intervals in the modern periodic table when elements are arranged in the increasing order of their atomic number.

like ionisation potential, electron positivity, electron negativity ,metallic and non metallic character and electron affinity.

ELECTRON NEGATIVITY

Its one of the periodic properties as, its the tendency of an atom to attract electrons itself when combined in a compound.

Factors affecting it :-

▶Atomic size increases, electron negativity decreases.

Electron negativity is the tendency to lose electrons. A small atom will lose electron readily than a large atom since nucleus has greater attraction on the electrons.

▶Nuclear charge increases ,electron negativity increases.

Nuclear charge increases similarly increases the tendency of the atom to lose electrons.

So, across a period from left to right atomic size decreases and nuclear charge increases electron negativity increases , therefore electron negativity increases.

Down a group from atomic radii increases therefore electron negativity decreases and nuclear charge increases therefore electron negativity should increase but since atomic radii dominates over nuclear charge, electron negativity decreases.

NOBLE GASES

Noble gases are stable so they neither loses nor gains electrons and hence find it difficult to lose electrons. So, the electron negativity of noble gases is zero.