Lanthanides and actinides resemble in

Options

A. electroic configuration
B. oxidation state
C. ionization energy
D. formation of complexes

Answer

To solve the question regarding the similarities between lanthanides and actinides, we will analyze each option provided in the question step by step.

### Step 1: Analyze Electronic Configuration
- **Lanthanides** have the general electronic configuration of \( [Xe] 6s^2 4f^{1-14} \).
- **Actinides** have the general electronic configuration of \( [Rn] 7s^2 5f^{1-14} \).
- Both groups fill the f-orbitals, thus their electronic configurations are similar in that they involve the filling of f-orbitals.

### Step 2: Analyze Oxidation States
- **Lanthanides** predominantly exhibit a +3 oxidation state, but can also show +2 and +4 states.
- **Actinides** also show a +3 oxidation state, but they can exhibit a wider range of oxidation states, including +4, +5, +6, +7, and +8.
- Therefore, the oxidation states are not similar between lanthanides and actinides.

### Step 3: Analyze Ionization Energy
- Ionization energy is influenced by the shielding effect. The 4f orbitals in lanthanides provide a greater shielding effect compared to the 5f orbitals in actinides.
- As a result, lanthanides generally have higher ionization energies than actinides.
- Thus, ionization energy is not a similarity.

### Step 4: Analyze Formation of Complexes
- Lanthanides have a lower tendency to form complexes compared to actinides.
- Actinides, due to their larger size and variable oxidation states, have a greater tendency to form complexes.
- Hence, this is also not a similarity.

### Conclusion
After analyzing all the options, the only similarity between lanthanides and actinides is their electronic configuration. Therefore, the answer to the question is:

**Answer: Electronic Configuration**

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