Lesson-specific diagram for Hydrocarbon families: alkanes, alkenes, and alkynes. It visualizes the reasoning sequence tied to $\mathrm{C_nH_{2n+2}},\;\mathrm{C_nH_{2n}},\;\mathrm{C_nH_{2n-2}}$. Text alternative: Hydrocarbon family formulas and unsaturation patterns connect names, structures, and molecular composition. Choose a representation that matches the chemical scale and evidence; do not infer more precision or mechanism than the data support.