The Development of Atomic Theory: From Democritus to Dalton

The law of multiple proportions suggests that when elements create multiple compounds, the masses of one element that combine with a fixed mass of another element are in ratios of ______ ______ ______.

______ ______ used the examination of compounds like water and carbon dioxide to provide ______ evidence for his atomic theory.

Dalton's theory was supported by the observation that the mass ratios of elements combining in compounds were consistent with the concept of ______, ______ atoms.

Year electron discovered

Significance of electron discovery

The nuclear model proposed by ______, ______, and ______ replaced the ______ model, which assumed a spread-out positive charge with electrons inside.

The experiment by Rutherford and his colleagues proved that the nucleus could deflect ______ particles, confirming its dense and massive nature.

Bohr's model year of introduction

Bohr's model relation to quantum theory

Significance of Moseley's X-ray experiments

The identification of the ______ is credited to ______ ______, who in ______ discovered positively charged particles known as hydrogen nuclei.

Key contributors to quantum mechanics in the 1920s