How many electron in Na (Z =11) have n = 3, l = 0 ?

Options

A. 1
B. 2
C. 0
D. 4

Explanation

To determine how many electrons in sodium (Na) with atomic number Z = 11 have quantum numbers n = 3 and l = 0, we can follow these steps:

### Step 1: Understand Quantum Numbers
The principal quantum number (n) indicates the energy level of an electron, while the azimuthal quantum number (l) indicates the shape of the orbital. For l = 0, the orbital is an s orbital.

### Step 2: Write the Electronic Configuration of Sodium
The electronic configuration of sodium (Na) can be written as:
- 1s² 2s² 2p⁶ 3s¹

This configuration shows how the electrons are distributed among the various orbitals.

### Step 3: Identify the Relevant Orbital
Since we are interested in n = 3 and l = 0, we are looking at the 3s orbital. The quantum number n = 3 indicates that we are in the third energy level, and l = 0 indicates that we are dealing with an s orbital.

### Step 4: Count the Electrons in the 3s Orbital
From the electronic configuration, we can see that the 3s orbital contains:
- 1 electron (from the configuration 3s¹).

### Conclusion
Thus, the number of electrons in sodium (Na) with quantum numbers n = 3 and l = 0 is **1**.