The Correct Order of Decreasing Electron Gain Enthalpy With the Negative Sign for Chalcogens is
By BYJU'S Exam Prep
Updated on: September 13th, 2023
1) O > S> Se > Te
2) S > Se > Te > O
3) S > Se > O > Te
4) S > Te > Se > O
The correct order of decreasing electro-gain enthalpy is S > Se > Te > O. Electron gain enthalpy is the change in enthalpy that occurs when an electron is added to a neutral gaseous atom to create a negative ion. Heat is primarily released during electron gain because a free electron loses energy when it becomes bonded to the atom and is affected by the negative charge. As a result, both the energy value and the electron gain enthalpy have negative signs. The negative sign only indicates the exothermic reaction. High negative energy levels will indicate a high electron affinity.
Electron Gain Enthalpy Trends along with Periodic Table:
- The nuclear charge rises, and the atomic size decreases as we walk along a period from left to right. As a result, the elements have a greater affinity for electrons, and the electron gain enthalpy decreases over time. As a result, as a period progresses, electron gain enthalpy becomes increasingly negative.
- The atomic radius grows, and the electron affinity lowers as we travel down a group. As we move down over a period, this causes the electron gain enthalpy to decrease. As a result, the smaller the group, the lower the electron gain enthalpy value.
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Correct Order of Decreasing Electron Gain Enthalpy
The term electron gain enthalpy refers to the change in enthalpy that occurs when one electron is added to a neutral gaseous atom to create a negative ion. A free electron loses energy when it bonds to the atom and is impacted by the negative charge, which is why heat emission primarily accompanies electron gain. As a result, both the electron gain enthalpy and the energy value have negative signs. The negative sign indicates only the exothermic reaction. High harmful energy levels will demonstrate a high electron affinity.
Detailed Explanation of Decreasing Electron Gain Enthalpy
- The periodic table’s group 16 contains chalcogens.
- Over a group of 16, we get O, S, Se, and Te from top to bottom.
- The trend should be O > S > Se > Te because we know that the electron gain enthalpy reduces as we travel down a group.
- However, due to their smaller size, which causes electron repulsion to the incoming electrons, elements with period 2 typically have less electron gain enthalpy.
- As a result, compared to all the other chalcogens, oxygen has less electron gain enthalpy because it is in period 2.
- The correct sequence is S > Se > Te > O.
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