what is ionisation energy?

Asked by Apoorva Sakshi | 20th Feb, 2014, 06:24: PM

Expert Answer:

The energy required to remove an electron from a neutral isolated gaseous stom and convert it into a positively charged gaseous ion is called ionisation energy or first ionisation energy.
Ionisation energy required to remove the second electron from a monovalent cation is called second ionization energy.
Similarly, the energy required to remove the third electron from a divalent cation is called the third ionisation energy.
Ionisation energy depends on:
(i) Atomic size
The greater the atomic size, the lesser the force of attraction. Since the electrons of the outermost shell lie further  away from the nucleus, thus make their removal easier,i.e., ionisation energy required is less.
(ii) Nuclear charge : The greater the nuclear charge, greater is the attraction for the electrons of the outermost shell. Therefore, the electrons in the outermost shell are more firmly held because of which greater energy is required to remove the electrons.

Answered by  | 21st Feb, 2014, 09:38: AM

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