Incorrect about `O_2` molecule?

Options

A. It is attracted towards magnetic field
B. It is most abundant element in the group
C. Most of its reactions are endothermic
D. It is little active under normal conditions

Explanation

To determine the incorrect statement about the O₂ molecule, let's analyze each option step by step.

### Step 1: Understand the Structure of O₂
The O₂ molecule consists of two oxygen atoms bonded together. Each oxygen atom has six valence electrons, and they share two pairs of electrons to form a double bond. This results in a stable diatomic molecule.

**Hint:** Remember that O₂ has a double bond due to the sharing of electrons between two oxygen atoms.

### Step 2: Evaluate the Magnetic Properties
The first option states that O₂ is attracted to a magnetic field. This is true because O₂ has unpaired electrons, which makes it paramagnetic. Therefore, it will be attracted to a magnetic field.

**Hint:** Consider the presence of unpaired electrons in determining magnetic properties.

### Step 3: Assess Abundance in Nature
The second option claims that O₂ is the most abundant element in its group. This is also correct, as oxygen is indeed one of the most abundant elements in the Earth's crust, comprising about 49.5% by weight.

**Hint:** Think about the composition of the Earth's crust when evaluating abundance.

### Step 4: Analyze Reaction Types
The third option states that most of O₂'s reactions are endothermic. This statement is incorrect. Most reactions involving oxygen, such as combustion, are exothermic, meaning they release heat.

**Hint:** Recall common reactions involving oxygen, like combustion, to determine if they release or absorb heat.

### Step 5: Evaluate Reactivity Under Normal Conditions
The fourth option mentions that O₂ is relatively inactive under normal conditions. This is true because O₂ has a stable electronic configuration and does not readily react unless certain conditions (like high temperatures) are met.

**Hint:** Consider the stability of the O₂ molecule and its electronic configuration to assess its reactivity.

### Conclusion
After evaluating all the options, the incorrect statement about the O₂ molecule is option number 3: "Most of its reactions are endothermic in nature."

**Final Answer:** The incorrect statement is option 3.