Which of the following statements are not true for hydrogen ?

Options

A. It exist as diatomic molecule
B. It has one electron in the outermost shell
C. It can lose an electron to from a cation which can freely exist
D. If from a large number of ionic compounds by losing an electron

Explanation

To determine which statements about hydrogen are not true, we can analyze each statement one by one.

1. **Statement 1: Hydrogen exists as a diatomic molecule (H2).**
- This statement is true. Hydrogen is commonly found in nature as a diatomic molecule, meaning it exists as two hydrogen atoms bonded together (H2).

2. **Statement 2: Hydrogen has one electron in the outermost shell.**
- This statement is also true. The electronic configuration of hydrogen is 1s¹, indicating that it has one electron in its outermost shell (the 1s orbital).

3. **Statement 3: Hydrogen can lose one electron to form a cation which can freely exist.**
- This statement is not true. While hydrogen can lose one electron to form a cation (H⁺), this cation is highly reactive and does not exist freely in nature. It is usually associated with other species in solution or in compounds.

4. **Statement 4: Hydrogen forms a large number of ionic compounds by losing electrons.**
- This statement is also not true. Although hydrogen can lose an electron, it does not typically form ionic compounds due to its high ionization energy. Instead, hydrogen primarily forms covalent bonds and compounds.

Based on the analysis:
- The statements that are not true for hydrogen are **Statement 3** and **Statement 4**.

### Summary of Findings:
- **True Statements:**
- Hydrogen exists as a diatomic molecule (H2).
- Hydrogen has one electron in the outermost shell.
- **Not True Statements:**
- Hydrogen can lose one electron to form a cation which can freely exist.
- Hydrogen forms a large number of ionic compounds by losing electrons.