Consider the ground state `Cr` atom `(Z = 24)` The number of electron with the azimuthal number `l = 1` and `2` respectively are

Options

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

Explanation

To determine the number of electrons in the chromium atom (Cr) with atomic number \( Z = 24 \) that have azimuthal quantum numbers \( l = 1 \) and \( l = 2 \), we first need to understand the electronic configuration of chromium.

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

### Step 2: Identify the Azimuthal Quantum Numbers
The azimuthal quantum number \( l \) corresponds to the type of orbital:
- \( l = 0 \) corresponds to s orbitals
- \( l = 1 \) corresponds to p orbitals
- \( l = 2 \) corresponds to d orbitals

### Step 3: Count the Electrons for \( l = 1 \) (p Orbitals)
In the electronic configuration:
- The p orbitals are filled as follows:
- \( 2p^6 \) contributes 6 electrons from the second energy level.
- \( 3p^6 \) contributes another 6 electrons from the third energy level.

Thus, the total number of electrons with \( l = 1 \) (p orbitals) is:
\[ 6 + 6 = 12 \]

### Step 4: Count the Electrons for \( l = 2 \) (d Orbitals)
In the electronic configuration:
- The d orbitals are filled as follows:
- \( 3d^5 \) contributes 5 electrons.

Thus, the total number of electrons with \( l = 2 \) (d orbitals) is:
\[ 5 \]

### Final Answer
Therefore, the number of electrons with \( l = 1 \) is 12 and with \( l = 2 \) is 5.

**Answer: 12 electrons (for \( l = 1 \)), 5 electrons (for \( l = 2 \)).**