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Shweta Thakur posted an Question

August 20, 2020 • 21:26 pm

30 points

IIT JAM
Chemistry (CY)

Why first transition elemants ionize by loss of 4s electron first not 3d

why first transition elemants ionize by loss of 4s electron first not 3d

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Priyanshu kumar Best Answer

Orbitals are filled in the lower energy orbitals first, then fill higher energy orbitals. The 3d orbitals have a slightly higher energy than the 4s orbitals. So because the 4s orbitals has the lower energy, it gets filled first. When 3d orbitals are filled, 4s is no longer lower in energy. Hence electrons are lost from 4s orbital first, because electrons lost first will come from the highest energy level (farthest away from the nucleus).
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Here 4s orbitals becomes outermost orbital and considered as a highest energy level as comparison to 3d as you know n increases energy of orbital increases. So electrons is removed first from 4s orbital then 3d orbital
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ok sir
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why 4s has high energy when we start filling electrons in 3d
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no shweta 4s has less n+l value so it filled first according to aufbau rule but for highest energy orbital concern 4s has high energy ...so removal of electron is firstly from 4s
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ok
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sir
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sir
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sir
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sir
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sir
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sir
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Dinesh khalmaniya 1

Orbitals are filled in the lower energy orbitals first, then fill higher energy orbitals. The 3d orbitals have a slightly higher energy than the 4s orbitals. so because the 4s orbitals has the lower energy, it gets filled first. When 3d orbitals are filled, 4s is no longer lower in energy. Hence electrons are lost from 4s orbital first, because electrons lost first will come from the highest energy level (furthest away from the nucleus).
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in other way, We say that the 4s orbitals have a lower energy than the 3d, and so the 4s orbitals are filled first. We know that the 4s electrons are lost first during ionisation. The electrons lost first will come from the highest energy level, furthest from the influence of the nucleus.
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got it??
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yes sir
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