Question

how to find ionisation enthalpy of an element??

Answer 1

The Electronegativity according to the Mullikan's scale is given by the formula

Electronegativity = (Ionisation Energy + Electron Affinity)/540

if Ionisation Energy & Electron Affinity(Electron Gain Enthalpy) are in KJ/mol

Electronegativity = (Ionisation Energy + Electron Affinity)/5.6

if Ionisation Energy & Electron Affinity(Electron Gain Enthalpy) are in Electron Volts(eV)

Mullikan's values = 2.8 * pauling values (the Ionisation Energy & Electron Affinity values must be given in electron volts(eV)).

This method is used when 2 of the 3 parameters used in the equation are known.

When the formula can't be used, and if the question asked has multiple choices, then I think the only way to answer the excursion is by using periodic properties of elements. Though the answer may not be precise

Answer 2

Calculating the ionization energy of an atom constitutes a part of modern physics that underlies many modern technologies. An atom consists of a central nucleus that contains positively charged protons and a number of neutrons specific to the given atom. A number of negatively charged electrons orbit the nucleus at various distances. The energy required to remove the lowest orbiting electron from the influence of the central protons is the ionization energy. Danish physicist Niels Bohr first calculated this energy for hydrogen in 1913, for which he won the Nobel Prize.

1. Determine what atom you want to use for calculating the ionization energy. Identify the value of "Z" for the atom using a periodic table. (Another name for the number Z is the atomic number.) The value for Z appears above the symbol for the atom. For example, Z equals 1 for hydrogen.

2. Decide how many electrons the atom contains. This number is the same as Z unless the atom has already lost some electrons.

3. Calculate the ionization energy, in units of electron volts, for a one-electron atom by squaring Z and then multiplying that result by 13.6.

4. For atoms with more than one electron, arrive at the ionization energy, in units of electron volts, by first subtracting one from Z, squaring the answer, and finally multiplying by 13.6.