Consider the ground state of Cr atom (Z =24). The numbers of electrons with the azimuthal quantum numbers, l= 1 and 2 are respectively

Options

A. 12 and 4
B. 12 and 5
C. 16 and 4
D. 16 and 5.

Explanation

To determine the number of electrons with azimuthal quantum numbers \( l = 1 \) and \( l = 2 \) in a chromium (Cr) atom (Z = 24) in its ground state, we need to follow these steps:

### Step 1: Write the Electronic Configuration of Chromium
The ground state electronic configuration of chromium is:
\[ 1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^6 \, 3d^5 \, 4s^1 \]

### Step 2: Identify the Azimuthal Quantum Number (l) for Each Subshell
- For \( s \)-orbitals, \( l = 0 \)
- For \( p \)-orbitals, \( l = 1 \)
- For \( d \)-orbitals, \( l = 2 \)

### Step 3: Count the Electrons in Subshells with \( l = 1 \)
- \( 2p^6 \): 6 electrons
- \( 3p^6 \): 6 electrons

Total electrons with \( l = 1 \) are:
\[ 6 (from \, 2p) + 6 (from \, 3p) = 12 \]

### Step 4: Count the Electrons in Subshells with \( l = 2 \)
- \( 3d^5 \): 5 electrons

Total electrons with \( l = 2 \) are:
\[ 5 (from \, 3d) \]

### Final Answer
- Number of electrons with \( l = 1 \): 12
- Number of electrons with \( l = 2 \): 5