Select whether the statement is true or false .Helium has the highest ionisation enthalpy.

Answer

To determine whether the statement "Helium has the highest ionization enthalpy" is true or false, we can follow these steps:

### Step 1: Understand Ionization Enthalpy
Ionization enthalpy (or ionization energy) is defined as the amount of energy required to remove an electron from an isolated gaseous atom.

**Hint:** Remember that ionization enthalpy is a measure of how strongly an atom holds onto its electrons.

### Step 2: Analyze the Periodic Trends
Ionization enthalpy generally increases across a period from left to right in the periodic table and decreases down a group. This is because as you move across a period, the atomic size decreases, leading to a stronger attraction between the nucleus and the electrons.

**Hint:** Consider how atomic size affects the attraction between the nucleus and electrons.

### Step 3: Locate Helium on the Periodic Table
Helium is located in Group 18 (the noble gases) and Period 1 of the periodic table. It has a very small atomic size, which contributes to its high ionization enthalpy.

**Hint:** Think about the position of helium in relation to other elements in the periodic table.

### Step 4: Compare Helium with Other Elements
While helium has a high ionization enthalpy, we must consider other elements. For example, hydrogen (which is also in Period 1) has a lower ionization enthalpy than helium. Among all elements, helium indeed has the highest ionization enthalpy.

**Hint:** Compare the ionization energies of helium with those of other elements, especially the noble gases.

### Step 5: Conclusion
Based on the analysis, we can conclude that the statement "Helium has the highest ionization enthalpy" is **True**.

**Final Answer:** True