State, whether the following statements is True or False:
An anion is larger than a cation if they are iso-electronic

Answer

To determine whether the statement "An anion is larger than a cation if they are iso-electronic" is true or false, we can follow these steps:

### Step 1: Understand Iso-electronic Species
Iso-electronic species are atoms or ions that have the same number of electrons. For example, Na⁺, Mg²⁺, and F⁻ are all iso-electronic because they each have 10 electrons.

**Hint:** Remember that iso-electronic species share the same electron count.

### Step 2: Compare Anions and Cations
When comparing anions and cations that are iso-electronic, we need to consider their nuclear charge. An anion (negatively charged ion) has more electrons than protons, while a cation (positively charged ion) has more protons than electrons.

**Hint:** Focus on the relationship between protons and electrons in anions and cations.

### Step 3: Analyze the Effect of Nuclear Charge
The greater the positive charge (more protons) in a cation, the stronger the attraction it exerts on its electrons, pulling them closer to the nucleus. Conversely, an anion, which has more electrons than protons, experiences less nuclear attraction per electron, resulting in a larger radius.

**Hint:** Consider how the number of protons affects the size of the ion.

### Step 4: Conclusion
Since anions have fewer protons relative to their electrons compared to cations, anions are indeed larger than cations when they are iso-electronic. Therefore, the statement is **True**.

**Final Answer:** The statement "An anion is larger than a cation if they are iso-electronic" is **True**.