The electronic configuration of an element is `1s^(2) 2s^(2) 2p^(6)3s^(2) 3p^(6) 4s^(2) 3d^(10) 4p^(2)` . What is the atomic number of the element which is just below the above element in the periodic table ?

Options

A. 36
B. 49
C. 50
D. 54

Answer

To determine the atomic number of the element that lies just below the given element with the electronic configuration \(1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^{10} 4p^2\), we will follow these steps:

### Step 1: Identify the Element
The given electronic configuration is:
- \(1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^{10} 4p^2\)

To find the atomic number, we need to count the total number of electrons in this configuration.

### Step 2: Count the Electrons
- \(1s^2\) contributes 2 electrons
- \(2s^2\) contributes 2 electrons
- \(2p^6\) contributes 6 electrons
- \(3s^2\) contributes 2 electrons
- \(3p^6\) contributes 6 electrons
- \(4s^2\) contributes 2 electrons
- \(3d^{10}\) contributes 10 electrons
- \(4p^2\) contributes 2 electrons

Now, adding these together:
\[ 2 + 2 + 6 + 2 + 6 + 2 + 10 + 2 = 32 \]

### Step 3: Identify the Element's Position in the Periodic Table
The total number of electrons, which is also the atomic number, is 32. This corresponds to the element Germanium (Ge).

### Step 4: Find the Element Below Germanium
Germanium (Ge) is located in Group 14 and Period 4 of the periodic table. The element directly below Germanium in the periodic table is Tin (Sn), which is in Group 14 and Period 5.

### Step 5: Determine the Atomic Number of Tin
The atomic number of Tin (Sn) is 50.

### Conclusion
Thus, the atomic number of the element which is just below the given element in the periodic table is **50**.

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