Wednesday, 27 May 2015

Ionization Energy


The ionization energy, or EI ionization potential is the energy needed to remove an electron in the ground state of an atom of an element in gas.1 The reaction condition can be expressed as follows:

\ A _ {(g)} + E {I} \ to A ^ + _ {(g)} \ + 1 \ bar e.

Where A _ {(g)} gaseous atoms of a given chemical element; E_i, the ionization energy and \ bar and an electron.

This energy corresponds to the first ionization. The second ionization potential is the energy required to subtract the second electron; this second ionization potential is always greater than the first, because the volume of a positive ion is less than the atom and the attractive electrostatic force that supports the second electron is greater in the positive ion in the atom as it is retained the same nuclear charge.

The ionization potential or energy expressed in electron volts, joules or kilojoules per mole (kJ / mol).

1 eV = 1.6 × 10-19 C × 1 V = 1.6 × 10-19 J

The elements of the same family or group, the ionization potential decreases with increasing atomic number, that is, from top to bottom.

However, the increase is not constant, as in the case of beryllium and nitrogen higher than what could be expected by comparison with the other elements in the same period values ​​are obtained. This increase is due to stability posed by s2 and s2 p3 configurations, respectively.

The higher ionization energy corresponds to the noble gases, since their electron configuration is the most stable, and therefore will have to provide more energy to boot electrons.