What is atomic number of element which have maximum electron affinity in Modern Periodic table.

Explanation

To determine the atomic number of the element with the maximum electron affinity in the Modern Periodic Table, we can follow these steps:

### Step 1: Understand Electron Affinity
Electron affinity refers to the amount of energy released when an electron is added to a neutral atom in the gas phase. Elements with high electron affinity tend to be more electronegative.

**Hint:** Remember that electron affinity is related to how easily an atom can gain an electron.

### Step 2: Identify the Group with High Electron Affinity
In the periodic table, the halogens (Group 17) are known for having high electron affinities. This is because they are one electron short of having a full outer shell, making them eager to gain an electron.

**Hint:** Think about which group of elements is known for being highly reactive and gaining electrons easily.

### Step 3: Determine the Element with Maximum Electron Affinity
Among the halogens, chlorine (Cl) has the most negative electron gain enthalpy, indicating that it has the highest electron affinity.

**Hint:** Compare the electron affinities of the halogens: fluorine, chlorine, bromine, and iodine.

### Step 4: Find the Atomic Number of Chlorine
The atomic number of chlorine is 17. This means that chlorine is the element with the maximum electron affinity in the Modern Periodic Table.

**Hint:** Look up the periodic table to confirm the atomic number of chlorine.

### Final Answer
The atomic number of the element which has maximum electron affinity in the Modern Periodic Table is **17** (Chlorine).

---