The amount of energy released when an atom in the gaseous state accepts an electron to form an anion. factor which affect electron affinity are: atomic size and Nuclear charge. As atomic radii increases, electron affinity increase. As nuclear charge increase, electron affinity increase. it decrease down a group and increases across a period. Explain.

Open in App

Solution

Electron affinity decreases down the groups and from right to left across the periods on the periodic table because the electrons are placed in a higher energy level far from the nucleus, thus causes a decrease from its pull. However, since the number of valence electrons increase going down the group, the element should be more stable and have higher electron affinity. As one goes down the period, the shielding effect increases, thus repulsion occurs between the electrons. This is why the attraction between the electron and the nucleus decreases as one goes down the group in the periodic table and electron affinity decreases down a group.

Suggest Corrections

Similar questions

Q. Assertion :Electron affinity of noble gas elements is zero. Reason: Electron affinity reflects the ability of an atom to accept an electron. It is the energy change that occurs when an electron is added to a gaseous atom. Atoms with stronger effective nuclear charge have greater electron affinity

Q. The electron affinity increases on moving from left to right along a period. Arrange the reasons in a proper sequence.
(a) The amount of energy released during the addition of an electrons increases from left to right along a period.
(b) Effective nuclear charge of the elements increases from left to right.
(c) The atomic size of the elements decreases from left to right.
(d) The tendency to gain electrons and form anion increases from left to right.

Q. As atomic size increases, electron affinity :

Q. Identify the correct statements from the following.
(a) An element with low ionization potential has high electropositivity and hence give out electrons easily.
(b) Due to decrease in ionization energy, in a group, the oxidizing property decreases.
(c) Electronegativity decreases along a period due to increase in nuclear charge and increase in atomic size.
(d) Due to increase in electron affinity the reducing property increases along a period.

On moving across a period, the atomic size decreases and nuclear charge increases and therefore the force of attraction exerted by the nucleus on the electron in the outermost shell increases.
For the process
$A_{(g)} + e^{-} \to A_{(g)}^{-}; Δ H = x a n d A_{(g)}^{-} \to A_{(g)} + e^{-}; Δ H = y$
Select correct alternate:

Join BYJU'S Learning Program