Which of the following factors contribute to the observed molecular geometry around a given atom?

• A. The atomic mass of the central atom
• B. The number of bonding pairs and lone pairs of electrons on the atom
• C. The color of the atom
• D. The number of protons in the nucleus

Answer: (B)

Verified step by step guidance

1. Understand that molecular geometry is determined by the arrangement of electron pairs around the central atom, which includes both bonding pairs (shared electrons in bonds) and lone pairs (non-bonding electrons).
2. Recall the Valence Shell Electron Pair Repulsion (VSEPR) theory, which states that electron pairs repel each other and arrange themselves to minimize repulsion, thus determining the shape of the molecule.
3. Recognize that factors like atomic mass, color of the atom, or the number of protons in the nucleus do not influence the spatial arrangement of electron pairs and therefore do not affect molecular geometry.
4. Focus on counting the total number of bonding pairs and lone pairs around the central atom to predict the molecular shape using VSEPR theory.
5. Use this information to identify the correct factor contributing to molecular geometry: the number of bonding pairs and lone pairs of electrons on the atom.