In the long or modern form of the periodic table, the element in the periodic table have been divided into four blocks, `s-p-d`-and `f`-. Each period begins with the filling of new energy shell. Two series of
`f`-block elements are placed at the bottom of the periodic table.
The last element of the `p`-block in the present periodic table is represented by the configuration, where `[X]` represents inert gas is

Options

A. `[X]7s^(2)p^(6)`
B. `[X]5f^(14),6d^(10),7s^(2)7p^(5)`
C. `[X]4f^(14),5d^(10),6s^(2)6p^(6)`
D. `[X]` None of the above

Explanation

To solve the question regarding the last element of the p-block in the modern periodic table represented by the electronic configuration where [X] represents an inert gas, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of the Periodic Table**:
The modern periodic table is divided into four blocks: s, p, d, and f. Each period corresponds to the filling of a new energy level or shell.

2. **Identify the Last Group in the p-Block**:
The last group in the p-block is Group 18, which consists of the noble gases. The elements in this group have complete valence shells.

3. **Determine the Period of the Last p-Block Element**:
The last element of the p-block is found in Period 6. This is important because it tells us which principal energy level (n) we are dealing with.

4. **Calculate the Number of Valence Electrons**:
For Group 18, the number of valence electrons is 8. This is because the group number (18) indicates that there are 8 electrons in the outermost shell (s and p orbitals).

5. **Write the Electronic Configuration**:
The electronic configuration for the last element in the p-block can be written as follows:
- The s-block contributes 2 electrons (6s²).
- The p-block contributes 6 electrons (6p⁶).
Therefore, the complete electronic configuration for the last element in the p-block is:
\[ [Xe] \, 6s^2 \, 6p^6 \]
where [Xe] represents the electronic configuration of the inert gas xenon, which has an atomic number of 54.

6. **Identify the Element**:
The element with the configuration [Xe] 6s² 6p⁶ corresponds to Radon (Rn), which has an atomic number of 86.

### Final Answer:
The last element of the p-block in the modern periodic table is represented by the configuration:
\[ [Xe] \, 6s^2 \, 6p^6 \]