Give the general variation of electron gain enthalpies in the periodic table.

Halogens have maximum negative electron gain enthalpy in the respective periods of the periodic table. Why?

Why is the value of electron-gain enthalpy negative?

What do you mean by electronegativity of an element? Discuss its variation along a period and down a group in the periodic table. Discuss with example.

What is the reason of periodicity in the periodic table?

Select the correct sequence of electron-gain enthalpy-

The periodicity is related to the electronic configuration that is all chemical and physical properties are a manifestation of the electronic configuration of the elements.the atomic and ionic radii genreally decrease in a period from left to right as a consequence the ionization enthalpies genrally increase and electron gain enthalpies become more negative across a period in other words the ionization enthalpy of the extreme left element element in a period is the least and the electron gain enthalpy of the element on the extreme right is the highest negative.this results into highly chemical reactivity at the two extremes and the lowest in the centre similarly down the group the increase in atomic and ionic radii result in gradual decrease in ionization enthalpies and a regular decrease (with exception in some third period elements)in electron gain enthalpies in the csea of main group elements. reducing and oxidizing behaviour of the elements metallic and non metallic character of elements acidic,basic,amphoteric and neutral charcter of the oxides of the elements The correct order of the metallic character is

Why Noble gases have zero electron gain enthalpy?

The number of elements present in the fifth period of the periodic table is