Question

Y O2 is less electron gain. enthalpy than s8​

Answer 1

This happens because of the fact that while adding an electron to the oxygen molecule it suffers high inter electronic repulsions from the atoms already present.

Size of oxygen is very small when compared to that of sulphur. Due to its compact size the positive nucleus holds the electrons together and tightly.

Since the electrons already present aren't much spread as in the case of Sulphur which has a larger surface area therefore while adding a new electron the electron suffers a huge inter electronic repulsion from the electrons already present.

This makes the value of Electron Gain Enthalpy very less in case of oxygen and places it in the last of its group.

The order is

S>Se>Te>Po>O

Hope this helps.

Answer 2

$Explanation$

★ Oxygen has less negative electron gain enthalpy than S because of small size of O.

★ Oxygen has much lower melting and boiling points than sulphur because oxygen is diatomic (O2) and sulphur is octatomic (S8).

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