Question

The I.P. of sodium is \[{\text{5}}{\text{.14eV}}\] . The I.P. of potassium could be:
A.Same as that of sodium
B.$5.68{\text{eV}}$
C.$4.{\text{34eV}}$
D.$10.28{\text{eV}}$

Answer 1

Hint: The minimum amount of energy required by an isolated gaseous atom to remove its outermost electron is known as its ionization energy or ionization potential. The ionization potential for an atom is inversely proportional to its radii.

Complete step by step answer:
The minimum amount of energy required to remove the outermost electron from the outermost shell of an atom is known as its ionization energy. Ionisation potential is the another name for ionization energy, previously ionization energy was called ionization potential. The ionization energy is determined experimentally, but we can compare the ionization potential or ionization energy by the size and charge present on the elemental atom.
Basically the ionization energy is determined by the position of elements in the periodic table. The trend for ionization energy changes from top to down and left to right. As we move down a group the size of elements keeps on increasing and hence the outermost electron moves away from the nucleus, due to which the attraction force decreases between the electrons and protons and finally the energy required to remove the electron also reduces. But as we move along a period the size of elemental atoms decreases and the ionization energy increases.
Here we are comparing sodium and potassium. The potassium element is placed below the sodium element in the group of periodic table so the ionization energy for potassium will be low as compared to that of sodium. The ionization potential for sodium is \[{\text{5}}{\text{.14eV}}\]. Therefore the I.P. value for potassium can only be $4.{\text{34eV}}$among all of the provided options.

Hence option (C) is correct.

Note:
Another term is also defined in chemistry related to addition of electrons to an isolated gaseous atom, this term is ‘Electron affinity’. Electron affinity basically describes the change in energy of a neutral atom when an electron is added to form an anion. It is simply opposite of the ionization energy.