The objective is to identify which element among the provided ones exhibits a +4 oxidation state, correlating it with its electron configuration.
Step 1: Electron Configuration Analysis. We examine the listed elements:
Cerium (Ce): Atomic number 58, electron configuration \( [Xe] 4f^1 5d^1 6s^2 \). In a +4 oxidation state, cerium achieves a \( [Xe] \) configuration by losing its 4f and 5d electrons.
Terbium (Tb): Atomic number 65, electron configuration \( [Xe] 4f^9 6s^2 \). While a +4 state would involve electron loss from 4f and 6s orbitals, Tb predominantly displays a +3 oxidation state.
Europium (Eu): Atomic number 63, electron configuration \( [Xe] 4f^7 6s^2 \). Europium commonly exists in +2 and +3 oxidation states, not typically +4.
Lutetium (Lu): Atomic number 71, electron configuration \( [Xe] 4f^{14} 5d^1 6s^2 \). Lutetium typically forms a +3 state by losing its 5d and 6s electrons, and a +4 state is not observed.
Step 2: Conclusion. Based on the electron configuration analysis, Cerium (Ce) is the sole element capable of achieving a +4 oxidation state by shedding its 4f and 5d electrons.
Consequently, the correct answer is \({\text{Ce}} \).
Calculate \( \Lambda_m^0 \) for acetic acid and its degree of dissociation (\( \alpha \)) if its molar conductivity is 48.1 \( \Omega^{-1} \, \text{cm}^2 \, \text{mol}^{-1} \).
Given that
\( \Lambda_m^0 (\text{HC}) = 426 \, \Omega^{-1} \, \text{cm}^2 \, \text{mol}^{-1} \),
\( \Lambda_m^0 (\text{NaCl}) = 126 \, \Omega^{-1} \, \text{cm}^2 \, \text{mol}^{-1} \),
\( \Lambda_m^0 (\text{CH}_3\text{COONa}) = 91 \, \Omega^{-1} \, \text{cm}^2 \, \text{mol}^{-1} \).
Europium (Eu) resembles Calcium (Ca) in the following ways:
(A). Both are diamagnetic
(B). Insolubility of their sulphates and carbonates in water
(C). Solubility of these metals in liquid NH3
(D). Insolubility of their dichlorides in strong HCI
Choose the correct answer from the options given below: