Mark the correct statements out of the following:

Options

A. He has highest `IE_(1)` in the periodic table.
B. `Cl` has the highest `EA` out of all elements in the periodic table.
C. `Hg` and `Br` are liquid at room temperature.
D. In any period, the atomic radius of the noble gas is lowest.

Answer

To determine the correct statements from the given options, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Statement 1: Helium has the highest first ionization energy in the periodic table.**
- **Analysis:** Helium, being a noble gas with the electron configuration of 1s², has a very small atomic size and a stable electron configuration. The first ionization energy is the energy required to remove the outermost electron from a neutral atom. Due to its small size and stable configuration, helium indeed has the highest first ionization energy among all elements.
- **Conclusion:** This statement is **correct**.

2. **Statement 2: Chlorine has the highest electron affinity out of all the elements in the periodic table.**
- **Analysis:** Electron affinity is the energy change when an electron is added to a neutral atom. Among the halogens, chlorine has the highest electron affinity. Although fluorine is smaller, the electron-electron repulsions in its compact 2p orbital reduce its electron affinity compared to chlorine. Thus, chlorine has a stronger tendency to accept an electron than any other element.
- **Conclusion:** This statement is **correct**.

3. **Statement 3: Mercury and bromine are liquid at room temperature.**
- **Analysis:** At room temperature, mercury (Hg) is a liquid due to its unique properties, and bromine (Br) is also a liquid. This is an unusual property as most elements are solid at room temperature.
- **Conclusion:** This statement is **correct**.

4. **Statement 4: The atomic radii of noble gases are the highest.**
- **Analysis:** This statement is incorrect. While noble gases have relatively large atomic radii compared to other elements in their periods, they do not have the highest atomic radii overall. Alkali metals generally have larger atomic radii than noble gases.
- **Conclusion:** This statement is **incorrect**.

### Final Conclusion:
The correct statements are:
- Statement 1: Helium has the highest first ionization energy in the periodic table. **(Correct)**
- Statement 2: Chlorine has the highest electron affinity out of all the elements in the periodic table. **(Correct)**
- Statement 3: Mercury and bromine are liquid at room temperature. **(Correct)**
- Statement 4: The atomic radii of noble gases are the highest. **(Incorrect)**

### Summary of Correct Statements:
- Statement 1, Statement 2, and Statement 3 are correct.

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