Question

The electronic configuration of Einsteinium is :(Given atomic number of Einsteinium = 99)

• A. [Rn] \( 5f^{12} 6d^0 7s^2 \)
• B. [Rn] \( 5f^{11} 6d^0 7s^2 \)
• C. [Rn] \( 5f^{13} 6d^0 7s^2 \)
• D. [Rn] \( 5f^{10} 6d^0 7s^2 \)

Answer 1

The Correct Option is B

To determine the electronic configuration of Einsteinium (Es), we need to follow the order of filling electrons into atomic orbitals according to the Aufbau principle, Hund's rule, and the Pauli exclusion principle.

The atomic number of Einsteinium is 99, indicating that it has 99 electrons.

General electronic configuration order is: \(1s \to 2s \to 2p \to 3s \to 3p \to 4s \to 3d \to 4p \to 5s \to 4d \to 5p \to 6s \to 4f \to 5d \to 6p \to 7s \to 5f \to 6d \to 7p\)

Let's break it down step by step for Einsteinium:

1. \([Rn]\) represents the electron configuration of Radon, which is the previous noble gas with an atomic number of 86.
2. After Radon, electrons will fill the \(7s\) orbital: \(7s^2\).
3. Next, electrons fill the \(5f\) orbitals. Since Einsteinium is part of the actinide series, the additional electrons will fill in the \(5f\) orbitals. Specifically, it has \(11\) electrons in these orbitals: \(5f^{11}\).
4. The \(6d\\) orbitals remain empty in this case: \(6d^0\).

Therefore, the full electron configuration of Einsteinium is written as \([Rn] \ 5f^{11} \ 6d^0 \ 7s^2\).

The correct option is:

[Rn] \( 5f^{11} 6d^0 7s^2 \)

Answer 2

The question asks for the electronic configuration of the element Einsteinium, which has an atomic number of 99. In order to determine the correct electronic configuration, we need to understand how electrons fill the atomic orbitals based on their energy levels, following the Aufbau principle.

1. Identify the Element and its Position:
   • Einsteinium is a member of the actinide series, and it has an atomic number of 99.
   • The electronic configuration will be an extension of the configuration of Radon (Rn), the nearest noble gas with a lower atomic number.
2. Determine the Configuration:
   • Starting from Radon, i.e., [Rn], which denotes: \(1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^6 \, 4s^2 \, 3d^{10} \, 4p^6 \, 5s^2 \, 4d^{10} \, 5p^6 \, 6s^2 \, 4f^{14} \, 5d^{10} \, 6p^6 \, 7s^2\).
   • Beyond Radon, electrons will fill:
     • \(5f\) orbitals, as actinides begin filling the 5f subshell. The configuration for Einsteinium will be completed by adding electrons to these orbitals.
   • Following the order of filling, Einsteinium will have: \([Rn] \, 5f^{11} 6d^0 7s^2\).
3. Comparison with Options:
   • Given options:
     1. [Rn] \(5f^{12} 6d^0 7s^2\)
     2. [Rn] \(5f^{11} 6d^0 7s^2\)
     3. [Rn] \(5f^{13} 6d^0 7s^2\)
     4. [Rn] \(5f^{10} 6d^0 7s^2\)
   • The correct option is: \([Rn] \, 5f^{11} 6d^0 7s^2\) which matches with option (2).

This configuration respects the electron filling order and Pauli's exclusion principle. Thus, option (2) is the correct electronic configuration of Einsteinium.