+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.
Let a line passing through the point $ (4,1,0) $ intersect the line $ L_1: \frac{x - 1}{2} = \frac{y - 2}{3} = \frac{z - 3}{4} $ at the point $ A(\alpha, \beta, \gamma) $ and the line $ L_2: x - 6 = y = -z + 4 $ at the point $ B(a, b, c) $. Then $ \begin{vmatrix} 1 & 0 & 1 \\ \alpha & \beta & \gamma \\ a & b & c \end{vmatrix} \text{ is equal to} $
Resonance in X$_2$Y can be represented as
The enthalpy of formation of X$_2$Y is 80 kJ mol$^{-1}$, and the magnitude of resonance energy of X$_2$Y is:
Lanthanoids are at the top of these two-row, while actinoids are at the bottom row.
Lanthanoids are inclusive of 14 elements, with atomic numbers 58-71:
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.