The electronic configuration of actinide elements are not known with certainity . Explain.

Explanation

### Step-by-Step Solution:

1. **Understanding Actinides**: The actinide series consists of 15 elements from actinium (Ac, atomic number 89) to lawrencium (Lr, atomic number 103). These elements are characterized by the filling of the 5f subshell.

2. **General Electronic Configuration**: The general electronic configuration of actinides can be represented as [Rn] 5f^n 6d^0-1 7s^2, where n can vary from 0 to 14. This indicates that the actinides have electrons in the 5f, 6d, and 7s subshells.

3. **Energy Levels of Electrons**: In actinides, the energy levels of the 5f and 6d orbitals are very close to each other. This proximity in energy means that electrons can easily transition between these orbitals.

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