Question

select the lewis structure that most accurately represents antimony pentachloride (sbcl₅). refer to a periodic table.

Explanation:

Step1: Determine central atom

Antimony pentachloride (\(SbCl_5\)) has antimony (Sb) as the central atom (since Sb is less electronegative than Cl, and in Lewis structures, the least electronegative atom is central, except H).

Step2: Count valence electrons

• Sb: Group 15, valence electrons = 5.
• Cl: Group 17, valence electrons = 7, 5 Cl atoms: \(5 \times 7 = 35\).
• Total valence electrons: \(5 + 35 = 40\).

Step3: Analyze each structure

• First structure: Central atom is Cl (incorrect, should be Sb).
• Second structure: Central atom Sb, but check bonds/lone pairs. Wait, no—wait, the fourth structure: Let's recheck. Wait, the correct structure should have Sb in the center, bonded to 5 Cl atoms. Each Cl has 3 lone pairs (6 electrons) and a single bond to Sb.
• Fourth structure: Sb in center, 5 single bonds to Cl (each Cl has 3 lone pairs). Let's check electrons: Each single bond is 2 electrons, 5 bonds: \(5 \times 2 = 10\). Each Cl has 6 lone pair electrons: \(5 \times 6 = 30\). Total: \(10 + 30 = 40\), which matches. Also, Sb (Group 15) can expand its octet (since it's in period 5, has d-orbitals) to form 5 bonds (5 + 5 = 10 electrons around Sb, which is allowed for period ≥3 elements). The second structure: Wait, no—wait the second structure: Sb bonded to 5 Cl? Wait, no, looking at the diagrams: The fourth structure (bottom right) has Sb in the center with 5 Cl atoms (top, bottom, left, two on right? Wait, no, the fourth structure: Sb in center, bonded to 5 Cl (top, bottom, left, and two on the right? Wait, no, the second structure: Wait, maybe I mislabeled. Wait, the correct Lewis structure for \(SbCl_5\) has Sb as central, 5 single bonds to Cl (each Cl has 3 lone pairs). So the structure with Sb in the center, 5 Cl atoms (each with 3 lone pairs) is the correct one (the bottom right, fourth structure? Wait, the options: Let's list them:

1. Top left: Central Cl, bonded to Sb and other Cls (incorrect, central should be Sb).
2. Top right: Sb bonded to 5 Cl? Wait, top right: Sb with bonds to 5 Cl? Wait, no, top right: Sb has bonds to 5 Cl? Wait, no, top right: Sb is bonded to 5 Cl? Wait, no, top right: Let's see: Sb in center, bonded to 5 Cl? Wait, no, top right: Sb has a bond to top Cl, bottom Cl, left Cl, and two right Cl? Wait, no, the fourth structure (bottom right) has Sb in center, with 5 Cl atoms (top, bottom, left, and two on the right? Wait, no, the bottom right structure: Sb in center, 5 single bonds (top Cl, bottom Cl, left Cl, and two Cl on the right, each with 3 lone pairs). Wait, actually, the correct structure is the one where Sb is central, bonded to 5 Cl atoms (each Cl has 3 lone pairs), which is the bottom right structure (fourth option). Wait, but let's confirm: Sb can have 5 bonds (since it's in period 5, can expand octet). So the structure with Sb in the center, 5 Cl atoms (each with 3 lone pairs) is correct.

Answer:

The Lewis structure with antimony (Sb) as the central atom, bonded to five chlorine (Cl) atoms (each Cl atom has three lone pairs of electrons) – the bottom - right structure (the fourth structure among the given options). (If we assume the options are labeled as: Top - left (1), Top - right (2), Bottom - left (3), Bottom - right (4), then the answer is 4. The structure with Sb in the center, 5 Cl atoms (each with 3 lone pairs) and single bonds from Sb to each Cl.)