Final answer:
Geometric isomers are molecules with the same molecular formula but differ in the placement of atoms alongside a double covalent bond, affecting their physical and chemical properties.
Step-by-step explanation:
The concept you're asking about refers to geometric isomers, which are molecules that share a chemical formula and have similar bonding patterns but differ in the placement of atoms alongside a double covalent bond. The classic example of geometric isomerism is found in molecules such as 2-butene, where the two methyl groups can either be on the same side (cis configuration) or on opposite sides (trans configuration) of the double bond. This difference in atom placement affects the molecule's physical and chemical properties even though the molecular formula remains constant.