Question

In which of the following elements, is the energy required to remove an electron from a neutral atom in its gaseous states the least?

• A. K
• B. Si
• C. P
• D. Na

Answer 1

The correct option is A

K

The explanation for the correct option A):

1. Ionization energy - It is the minimum energy required to remove the most loosely bound electron of an isolated neutral gaseous atom or molecule.
2. Trend of the ionization energy: In groups, the ionization energy decreases from top to bottom and increases from left to right across the period.
3. The elements in the periodic table's lower left-hand section have the lowest ionization energies (and so are the most chemically active metals), whereas those in the upper right-hand region have the highest ionization energies (and are thus the most chemically active nonmetals).
4. Ionization energy decreases as we move down the group from Lithium to Cesium. It is easier to remove an electron from K metal than from Na metal.
5. Ionization energy increases as we progress through the third period. It is easier to remove one electron from Si than it is from P.
6. Thus, from the above explanation; the potassium (K) element needs the least energy to remove an electron from a neutral atom in its gaseous state.

Hence, option (A) is correct.