The electronic configuration of the following elements K 19 , Mn 25 , Ca 20 are given. K 19 = 1s 2 2s 2 2p 6 3s 2 3p 6 4s x Mn 25 = 1s 2 2s 2 2p 6 3s 2 3p 6 3d 5 4s y Ca 20 = 1s 2 2s 2 2p 6 3s 2 3p 6 4s z The product of x, y, and z is:

Explanation

To solve the question, we need to determine the values of x, y, and z from the electronic configurations of the elements potassium (K), manganese (Mn), and calcium (Ca).

### Step-by-Step Solution:

1. **Identify the electronic configuration of Potassium (K)**:
- The atomic number of K is 19.
- The electronic configuration is given as:
\[ 1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^6 \, 4s^x \]
- We know that K has 19 electrons. The first 18 electrons fill the 1s, 2s, 2p, 3s, and 3p orbitals.
- Therefore, the remaining electron will go into the 4s orbital:
\[ 4s^1 \quad \Rightarrow \quad x = 1 \]

2. **Identify the electronic configuration of Manganese (Mn)**:
- The atomic number of Mn is 25.
- The electronic configuration is given as:
\[ 1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^6 \, 3d^5 \, 4s^y \]
- For Mn, the first 18 electrons fill the 1s, 2s, 2p, 3s, and 3p orbitals. The next 5 electrons will fill the 3d orbital, and the last electron will fill the 4s orbital:
\[ 3d^5 \, 4s^2 \quad \Rightarrow \quad y = 2 \]

3. **Identify the electronic configuration of Calcium (Ca)**:
- The atomic number of Ca is 20.
- The electronic configuration is given as:
\[ 1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^6 \, 4s^z \]
- For Ca, the first 18 electrons fill the 1s, 2s, 2p, 3s, and 3p orbitals. The next 2 electrons will fill the 4s orbital:
\[ 4s^2 \quad \Rightarrow \quad z = 2 \]

4. **Calculate the product of x, y, and z**:
- Now we have:
\[ x = 1, \quad y = 2, \quad z = 2 \]
- The product is:
\[ x \cdot y \cdot z = 1 \cdot 2 \cdot 2 = 4 \]

### Final Answer:
The product of x, y, and z is **4**.