How many electrons with l=2 are there in an atom having atomic number 24 ?

Options

A. 1
B. 5
C. 3
D. 4

Explanation

To determine how many electrons with \( l = 2 \) are present in an atom with atomic number 24, we need to follow these steps:

### Step 1: Identify the Atomic Number
The atomic number given is 24. This means the atom has 24 electrons since the number of protons equals the number of electrons in a neutral atom.

### Step 2: Write the Electron Configuration
We need to write the electron configuration for the element with atomic number 24. The element with atomic number 24 is chromium (Cr). The electron configuration for chromium is:
\[ \text{Cr: } [\text{Ar}] 4s^1 3d^5 \]
Here, \([\text{Ar}]\) represents the electron configuration of argon, which has an atomic number of 18.

### Step 3: Identify the Orbitals and Their Quantum Numbers
In the electron configuration:
- The \( 4s \) orbital corresponds to \( l = 0 \) (s orbital).
- The \( 3d \) orbital corresponds to \( l = 2 \) (d orbital).

### Step 4: Count the Electrons in the d Orbital
From the electron configuration \( 4s^1 3d^5 \), we see that there are 5 electrons in the \( 3d \) orbital.

### Conclusion
Therefore, the number of electrons with \( l = 2 \) (which corresponds to the d orbital) in an atom with atomic number 24 is **5**.