Question

How do you know which molecule to put in the center of a Lewis diagram?

A) The smallest atom goes in the center
B) The most electronegative atom goes in the center
C) The atom with the highest atomic number goes in the center
D) The atom with the lowest atomic number goes in the center

Answer 1

To identify the central molecule in a Lewis diagram, choose the least electronegative element, as it typically forms the most bonds. Hydrogen and halogens are usually terminal and not central.

Step-by-step explanation:

To determine which molecule to put in the center of a Lewis diagram, you typically choose the least electronegative element. This element tends to be the one that can form the most bonds with surrounding atoms. Generally, hydrogen and the halogens (like fluorine, chlorine, etc.) are terminal, meaning they are almost always connected to only one other atom and therefore are not placed in the center. For example, in carbon tetrachloride (CCl4) and the carbonate ion (CO3²⁻), carbon (C) is less electronegative than chlorine or oxygen and is listed first in the chemical formula, making carbon the central atom.