Solution By Steps

Step 1: Lewis Structure

To determine the molecular shape of BrCN, we first need to draw the Lewis structure.

Br has 7 valence electrons, C has 4, and N has 5.

Total valence electrons = 7 (Br) + 4 © + 5 (N) + 1 (extra electron) = 17 electrons.

Connect Br to C to N with single bonds and place the remaining electrons around the atoms to satisfy the octet rule.

Step 2: Electron Pair Arrangement

Identify the electron pair arrangement around the central atom.

Br has 2 bonding pairs and 3 lone pairs.

The electron pair arrangement is trigonal bipyramidal.

Step 3: Molecular Shape

Determine the molecular shape based on the electron pair arrangement.

In BrCN, the lone pairs are in equatorial positions, and the bonding pairs are axial.

The molecular shape is linear.

Final Answer

The molecular shape of BrCN is linear.

Key Concept

Molecular Geometry

Key Concept Explanation

Molecular geometry describes the arrangement of atoms in a molecule. It is crucial in understanding a molecule’s physical and chemical properties, such as polarity and reactivity.