Question

select the lewis structure that most accurately represents iodine pentachloride (icl₅). refer to a periodic table.

Explanation:

To determine the correct Lewis structure for \( \text{ICl}_5 \), we analyze the central atom and bonding:

Step 1: Identify the Central Atom

Iodine (I) is the central atom in \( \text{ICl}_5 \) because it is less electronegative than chlorine (Cl) and can expand its octet (iodine is in period 5, so it has access to d - orbitals for expanded valence). Chlorine is a terminal atom here.

Step 2: Analyze Bonding and Lone Pairs

• Iodine forms 5 single bonds with chlorine atoms (since the formula is \( \text{ICl}_5 \), indicating 5 I - Cl bonds).
• Each Cl atom has 3 lone pairs (to satisfy the octet rule: 7 valence electrons for Cl, 1 used in bonding, so \( 7 - 1=6 \) electrons, or 3 lone pairs).
• Iodine, after forming 5 bonds, has \( 7 - 5 = 2 \) valence electrons (1 lone pair) left, but in the Lewis structure, the central atom is I, with 5 Cl atoms bonded to it.

Looking at the options:

• The first option (top - left) has I as the central atom, with 5 Cl atoms bonded to it (one Cl above, one below, one left, and two on the right, all with correct lone pairs on Cl).
• The second option incorrectly has Cl as the central atom (not possible, as I is less electronegative and should be central).
• The third option incorrectly has I as a terminal atom (Cl is central, which is wrong).
• The fourth option: While I is central, the lone pair on I is not shown correctly in the context of the structure (or the bonding arrangement is less accurate than the first option).

The first structure (top - left) correctly shows I as the central atom with 5 Cl atoms bonded to it, each Cl having 3 lone pairs, and I with the appropriate bonding (5 single bonds) and lone pair (though the lone pair on I may be implied or shown appropriately in the structure).

Answer:

The Lewis structure in the top - left box (with I as the central atom, bonded to five Cl atoms, each Cl having three lone pairs) is the correct one.