Electron gain enthalpy of an element may be defined as the energy released when a neutral isolated gaseous atom accepts an extra electron to form the gaseous negative Ion i.e. anion.It is denoted by
Δ eg H.
Greater the amount of energy released in the above process, higher is the electron gain enthalpy of the element. The electron gain enthalpy of a element is a measure of the firmness or strength with which an extra electron is bound to it.
Electron gain enthalpy is measured in electron volts per atom or kJ per mole.
The process of adding an electron to the atom can be either exothermic or endothermic.
Energy is released when an electron is added to the atom. Therefore, the electron gain enthalpy is negative.
The electron gain enthalpy for halogens is highly negative because they can acquire the nearest stable noble gas configuration by accepting an extra electron.
Noble gases have large positive electron gain enthalpy because the extra electron has to be placed in the next higher principal quantum energy levels there by producing highly unstable electronic configuration.
After the addition of 1 electron, the atoms becomes negatively charged and the second electron is to be added to a negatively charged Ion. But the addition of second electron is opposed by the electrostatic repulsion and hence the energy has to be supplied for the addition of second electron. The second electron gain enthalpy of an element is positive.
When an electron is added to oxygen atom to form O¯ ion ,energy is released.But when another electron is added to O¯ ion to form O2- ion, the energy is absorbed to overcome the strong electrostatic repulsion between the negatively charged O¯ ion and second electron being added.
Gaurav Seth 4 years, 1 month ago
Electron gain enthalpy of an element may be defined as the energy released when a neutral isolated gaseous atom accepts an extra electron to form the gaseous negative Ion i.e. anion.It is denoted by
Δ eg H.
Greater the amount of energy released in the above process, higher is the electron gain enthalpy of the element. The electron gain enthalpy of a element is a measure of the firmness or strength with which an extra electron is bound to it.
Electron gain enthalpy is measured in electron volts per atom or kJ per mole.
The process of adding an electron to the atom can be either exothermic or endothermic.
Energy is released when an electron is added to the atom. Therefore, the electron gain enthalpy is negative.
The electron gain enthalpy for halogens is highly negative because they can acquire the nearest stable noble gas configuration by accepting an extra electron.
Noble gases have large positive electron gain enthalpy because the extra electron has to be placed in the next higher principal quantum energy levels there by producing highly unstable electronic configuration.
After the addition of 1 electron, the atoms becomes negatively charged and the second electron is to be added to a negatively charged Ion. But the addition of second electron is opposed by the electrostatic repulsion and hence the energy has to be supplied for the addition of second electron. The second electron gain enthalpy of an element is positive.
When an electron is added to oxygen atom to form O¯ ion ,energy is released.But when another electron is added to O¯ ion to form O2- ion, the energy is absorbed to overcome the strong electrostatic repulsion between the negatively charged O¯ ion and second electron being added.
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