The shape of the water molecule is_______?

Step 1: Analyze the question We are asked for the shape (molecular geometry) of H₂O. This is answered with VSEPR theory (Valence Shell Electron Pair Repulsion).

Step 2: Explain the concept Electron pairs around a central atom repel each other and arrange themselves as far apart as possible. Lone pairs repel more strongly than bonding pairs, so they squeeze the bond angle smaller.

Step 3: Solution

• Central atom: Oxygen (6 valence electrons, group 16).
• Two electrons are shared with two hydrogen atoms, giving 2 bond pairs.
• The remaining 4 electrons form 2 lone pairs.
• Total = 4 electron pairs, so the electron arrangement is tetrahedral.
• Only 2 of those 4 pairs are bonds. The two lone pairs push the O-H bonds closer together, so the molecular shape is bent, also called V-shaped or angular.
• The bond angle is about 104.5°, compared with 109.5° in a perfect tetrahedron.

Why not the others?

• A. Linear: this would need a 180° angle and no lone pairs, as in CO₂.
• B. Pyramidal: this needs 3 bond pairs and 1 lone pair, as in NH₃.
• C. Tetrahedral: this needs 4 bond pairs and no lone pairs, as in CH₄. Water's electron-pair geometry is tetrahedral, but its molecular shape is not.

Answer: The shape of the water molecule is V-shaped, which is option D.

Exam tip: Remember the pattern with 4 electron pairs:

• 0 lone pairs → CH₄ → tetrahedral
• 1 lone pair → NH₃ → pyramidal
• 2 lone pairs → H₂O → V-shaped (bent)

Count the lone pairs, and the shape follows.