What is electron affinity?
The amount of energy released when an electron added to a neutral & isolated gaseous atom in its ground state to form monovalent anion is called electron affinity .It is denoted by E.A.
X(g)+e-=X-(g)+E.A
What is Ionization energy?
And The amount of energy required to remove an electron from neutral and isolated gaseous atom in its ground state to form monovalent cation is called Ionization energy.It is denoted by I.E.
M(g)=M*+e-
Variation of ionization energy along period and group:
When we move from left to right in a particular period ,the atomic size of an atom decreases and Valence electrons are strongly attracted towards nucleus.Hence,large amount of energy required to release Valence electron.Therefore electron affinity increases along the period.
When we move from top to bottom in a particular group ,the atomic size of an atom increases and Valence electrons are loosely attracted towards nucleus.Hence,small amount of energy required to release Valence electron.Therefore electron affinity decreases along the group.
What is electropositivity and why alkali metals are most electro positive elements in periodic table ?
The tendency to loose or donate electron and form cation(positively charged) is electropositivity.Especialy metals and alkaline metals are electropositive elements .all metals are strongly electro positive in nature because alkali metals have largest atomic size.Metallic property increases when move from top to bottom in particular group it is due to increase in atomic size and decrease in ionization energy .that's why Cs is most electropositivite element in a periodic table.hence electrical conductivity or ionic mobility increases from Li to Cs.
li<Na<K<Rb<Cs
from lithium to caesium
- degree of hydration increases
- ionic size increases
- size of hydrated cation is decreasing
what is electronegativity?
The tendency to gain or attract electron and form anion( negatively charge) is electronegativity .Non- metals are especially known to have high electro negative charge .
