How many electron in Ca (Z =20) have n = 3, l = 1 ?

Options

A. 0
B. 1
C. 2
D. 6

Explanation

To determine how many electrons in calcium (Ca) with atomic number Z = 20 have quantum numbers n = 3 and l = 1, we can follow these steps:

### Step 1: Understand the Quantum Numbers
- The principal quantum number (n) indicates the energy level of an electron. Here, n = 3 means we are looking at the third energy level.
- The azimuthal quantum number (l) indicates the subshell. For l = 1, this corresponds to the p subshell.

### Step 2: Write the Electronic Configuration of Calcium
- The atomic number of calcium is 20, which means it has 20 electrons. The electronic configuration of calcium can be written as:
- 1s² 2s² 2p⁶ 3s² 3p⁶ 4s²

### Step 3: Identify the Electrons in the n = 3 and l = 1 State
- In the electronic configuration, we focus on the third energy level (n = 3):
- The 3s subshell (l = 0) has 2 electrons.
- The 3p subshell (l = 1) has 6 electrons.

### Step 4: Count the Electrons in the 3p Subshell
- Since we are interested in the 3p subshell (where n = 3 and l = 1), we find that there are 6 electrons in this subshell.

### Conclusion
- Therefore, the number of electrons in calcium (Z = 20) that have n = 3 and l = 1 is **6**.

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