Amedeo Avogadro

Revolutionized chemistry through his molecular theory that transformed atomic understanding

Amedeo Avogadro (1776–1856), an Italian scientist, made foundational contributions to molecular chemistry despite initial obscurity. His 1811 hypothesis—that equal gas volumes contain equal molecule numbers—laid groundwork for modern atomic theory.

Key breakthroughs include:

• Distinguishing atoms from molecules
• Establishing water's H₂O formula
• Inspiring later scientists like Ernest Rutherford

Avogadro's Number (6.022×10²³), though posthumously named, became chemistry's cornerstone. As explained in Science History Institute records, his work resolved contradictions between John Dalton and Joseph Gay-Lussac's theories.

His 1814 paper Mémoire sur les masses relatives systematically applied atomic theory to chemical reactions. The table below shows his impact:

Though ignored during his lifetime, his theories gained recognition through Stanislao Cannizzaro's 1860 advocacy, forever changing chemical education and research methodologies.