Question

For the elements with the electron affinities given in the table in the introduction, which element is most likely to accept an electron? hints for the elements with the electron affinities given in the table in the introduction, which element is most likely to accept an electron? be p o

Answer 1

Answer: The element which easily accepts electron is oxygen.

Explanation: Electron affinity of an element is defined as the amount of energy which is released when 1 mole of gaseous atom gains one electron to form 1 mole of gaseous negative ion. This energy is expressed in the units of kJ/mol.

• For Beryllium

Electronic configuration of Beryllium = $1s^22s^2$       $(E_{EA}=0kJ/mol)$

As the sub-shells of beryllium atom is fully filled. Hence, it will not require any extra electron to form negative ion.

• For Phosphorous

Electronic configuration of Phosphorous = $1s^22s^22p^63s^22p^3$              $(E_{EA}=71kJ/mol)$

As the 3p sub-shell of this element can acquire electron to form a negative ion. But, the energy released will be less because 3p sub-shell is not close to the nucleus and the extra electron will not be held strongly by the nucleus.

• For Oxygen

Electronic configuration of Oxygen = $1s^22s^22p^4$       $(E_{EA}=141kJ/mol)$

As the 2p sub-shell can acquire electron to form a negative ion. The energy released will be more because 2p sub-shell is close to the nucleus and the extra electron will be held strongly by the nucleus.

So, out of the elements given, order of electron affinity values will be:

O > P > Be

The element which will easily accept an electron will be oxygen.