ELECTRON AFFINITY AND ITS TRENDS Chemistry.pptx

A ppt made on Electron affinity and its trends for chemistry.
Science knowledge

1. CHEMISTRY PRESENTATION TOPIC -: ELCTRON AFFINITY AND ITS TRENDS SUBMITTED TO -: Ms. JAYSREE VISHWAS

2. ELECTRON AFFINITY Energy that occur when an electron is added to a neutral atom in the gaseous state to form a negative ion . X(g) + e- ----  X.(g) E = electron attachment energy Electron affinity = - E (electron attachment)

3. SECOND ELECTRON AFFINITY :- Second electron affinity of n element M(g) is defined as the amount of energy required to add one more electron to its mononegative anion,to form dinegative anion. The addition of second electron to uni - negative ion is an endothermic process

4. Factors Affecting Electron Affinity : Nuclear Charge : More the nuclear charge of the atom more strongly will it attract additional electron. Therefore, electron affinity increases as the nuclear charge increases. Atomic Size : The smaller the size of atom smaller will be the distance between the extra electron and the nucleus. Therefore, electrostatic force of attraction will be more and the electron affinity will be higher. Electron Configuration : Atoms having stable electronic configuration (i.e. those having completely filled or half filled outer orbitals) do not show much tendency to add extra electron, so have either zero or very low electron affinities.

5. Periodic Trends : Electron affinity values generally increases on moving left to right in a period. Electron affinities undergo a general decrease down a group. Electron affinity is usually exothermic. Electron affinities can be obtained by using Born-Haber cycle.

6. In general, electron affinity becomes more exothermic as you go from left to right across a row. The first occurs between Groups IA and IIA. Added electron must go in p-orbital , not s-orbital. Electron is farther from nucleus and feels repulsion from s-electrons.

7. THANK YOU SUBMITTED BY : NABEEL KHAN