Which of the following is the smallest in size?

Options

A. `Br`
B. `I^(-)`
C. `I`
D. `Br^(-)`

Answer

To determine which of the given species is the smallest in size, we need to analyze the ionic sizes of bromine (Br) and iodine (I), as well as their respective ions (Br⁻ and I⁻). Here’s a step-by-step solution:

### Step 1: Identify the Elements and Their Positions
We have bromine (Br) and iodine (I). Bromine is located above iodine in Group 17 of the periodic table.

**Hint:** Remember that as you move down a group in the periodic table, atomic size generally increases due to the addition of electron shells.

### Step 2: Compare the Atomic Sizes
Since bromine is above iodine in the periodic table, bromine has a smaller atomic size compared to iodine.

**Hint:** Compare the positions of the elements in the periodic table to determine relative sizes.

### Step 3: Analyze the Ions
Next, we look at the ions:
- Br (neutral bromine)
- Br⁻ (bromide ion)
- I (neutral iodine)
- I⁻ (iodide ion)

**Hint:** When an atom gains an electron to form an anion, its size increases due to increased electron-electron repulsion.

### Step 4: Determine the Size of the Ions
- The bromide ion (Br⁻) is larger than the neutral bromine atom (Br) because it has gained an electron.
- The iodide ion (I⁻) is larger than the neutral iodine atom (I) for the same reason.

**Hint:** Remember that gaining an electron increases the size of the ion.

### Step 5: Compare the Sizes
Now we compare the sizes:
- Br (neutral) vs. Br⁻ (bromide ion)
- I (neutral) vs. I⁻ (iodide ion)

Since Br is smaller than both Br⁻ and I⁻, and I is larger than Br, we conclude that:
- Br is smaller than Br⁻
- Br is smaller than I
- Br is smaller than I⁻

**Hint:** Focus on the comparison between the neutral atoms and their corresponding ions.

### Conclusion
From the analysis, we find that the smallest species among the given options is the neutral bromine atom (Br).

**Final Answer:** The smallest in size is Br (bromine).