Which of the following elements can form both ionic and covalent bonds ?

Options

A. Argon
B. Hydrogen
C. Iron
D. Neon

Explanation

To determine which of the given elements can form both ionic and covalent bonds, we will analyze each option step by step.

### Step 1: Identify the Elements
The elements provided are:
- A: Argon (Ar)
- B: Hydrogen (H)
- C: Iron (Fe)
- D: Neon (Ne)

### Step 2: Analyze Noble Gases
Argon and Neon are noble gases. Noble gases are characterized by having a complete valence shell, which makes them generally unreactive. Therefore, they do not form either ionic or covalent bonds.

**Hint:** Noble gases have full valence shells and do not typically form bonds.

### Step 3: Analyze Hydrogen
Hydrogen is unique because it can form both types of bonds:
- **Ionic Bond:** Hydrogen can form an ionic bond when it reacts with alkali metals. For example, in sodium hydride (NaH), sodium (Na) donates an electron to hydrogen, resulting in Na⁺ and H⁻ ions.
- **Covalent Bond:** Hydrogen can also form covalent bonds, as seen in hydrogen chloride (HCl), where it shares an electron with chlorine (Cl), resulting in a covalent bond.

**Hint:** Hydrogen can either lose an electron to form a positive ion (ionic bond) or share electrons (covalent bond).

### Step 4: Analyze Iron
Iron (Fe) is a transition metal and primarily forms ionic bonds by losing electrons to form cations (Fe²⁺ or Fe³⁺). While it can participate in covalent bonding in certain complex compounds, it is not typically known for forming covalent bonds in the same way that nonmetals do.

**Hint:** Transition metals like iron primarily form ionic bonds but can sometimes participate in covalent bonding.

### Step 5: Conclusion
Based on the analysis:
- Argon (A) and Neon (D) do not form bonds.
- Iron (C) primarily forms ionic bonds and occasionally covalent bonds but is not a common example.
- Hydrogen (B) can form both ionic and covalent bonds.

Thus, the element that can form both ionic and covalent bonds is **B: Hydrogen**.

**Final Answer:** B: Hydrogen