The ′f′ orbitals are half and completely filled, respectively in lanthanide ions
[Given: Atomic no. Eu, 63; Sm, 62; Tm, 69; Tb, 65; Yb, 70; Dy, 66]
[Given: Atomic no. Eu, 63; Sm, 62; Tm, 69; Tb, 65; Yb, 70; Dy, 66]
- \(Eu^{2+}\) and \(Tm^{2+}\)
- \(Sm^{2+}\) and \(Tm^{3+}\)
- \(Tb^{4+}\) and \(Yb^{2+}\)
- \(Dy^{3+}\) and \(Yb^{3+}\)
The Correct Option is C
Solution and Explanation
| +2 | +3 | +4 | |
|---|---|---|---|
| Eu | \(4f^7\) | \(4f^6\) | |
| Tm | \(4f^{13}\) | \(4f^{12}\) | |
| Sm | \(4f^6\) | \(4f^5\) | |
| Tb | \(4f^9\) | \(4f^8\) | \(4f^7\) |
| Yb | \(4f^{14}\) | \(4f^{13}\) | |
| Dy | \(4f^{10}\) | \(4f^9\) |
Hence, the pair \(Tb^{+4} Yb^{+2}\) have half filled and completely filled \(f\) subshells respectively.
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Concepts Used:
Lanthanoids
Lanthanoids are at the top of these two-row, while actinoids are at the bottom row.
Properties of Lanthanoids
Lanthanoids are inclusive of 14 elements, with atomic numbers 58-71:
- Cerium - Xe 4f1 5d1 6s2
- Praseodymium - Xe 4f3 6s2
- Neodymium - Xe 4f4 6s2
- Promethium - Xe 4f5 6s2
- Samarium - Xe 4f6 6s2
- Europium - Xe 4f7 6s2
- Gadolinium - Xe 4f7 5d1 6s2
- Terbium - Xe 4f9 6s2
- Dysprosium - Xe 4f10 6s2
- Holmium - Xe 4f11 6s2
- Erbium - Xe 4f12 6s2
- Thulium - Xe 4f13 6s2
- Ytterbium - Xe 4f14 6s2
- Lutetium - Xe 4f14 5d1 6s2
These elements are also called rare earth elements. They are found naturally on the earth, and they're all radioactively stable except promethium, which is radioactive. A trend is one of the interesting properties of the lanthanoid elements, called lanthanide contraction.