Oxidation number of iodine varies from -

Options

A. `-1" to "+1`
B. `-1" to "+7`
C. `+3" to "+5`
D. `-1" to "+5`

Answer

To determine the variation of oxidation numbers of iodine, we can follow these steps:

### Step 1: Understand Oxidation Number
The oxidation number (or oxidation state) of an element in a compound indicates the number of electrons that an atom can lose, gain, or share when forming chemical bonds.

**Hint:** Remember that oxidation numbers can be positive, negative, or zero, depending on the element's electron configuration and bonding.

### Step 2: Determine the Electron Configuration of Iodine
Iodine (I) has the electronic configuration of krypton (Kr) followed by 4d10 5s2 5p5. This means that iodine has a total of 7 valence electrons (2 from 5s and 5 from 5p).

**Hint:** The valence electrons are crucial in determining how many electrons an atom can gain or lose.

### Step 3: Analyze the Tendency of Iodine
Iodine can either:
- Gain 1 electron to achieve a stable noble gas configuration, resulting in an oxidation number of -1.
- Lose its 7 valence electrons one by one, leading to positive oxidation states.

**Hint:** Consider both gaining and losing electrons to find the range of oxidation states.

### Step 4: Identify Possible Oxidation States
When iodine gains an electron:
- Oxidation number = -1

When iodine loses electrons:
- Possible oxidation numbers can be +1, +2, +3, +4, +5, +6, and +7.

**Hint:** The maximum positive oxidation state corresponds to the total number of valence electrons.

### Step 5: Conclusion
The oxidation number of iodine varies from -1 (when it gains an electron) to +7 (when it loses all its valence electrons). Therefore, the correct answer is that the oxidation number of iodine varies from -1 to +7.

**Final Answer:** The oxidation number of iodine varies from -1 to +7.