Atomic Theory Flashcard

Front

Who was the ancient Greek philosopher that first proposed the idea of atoms?

Back

Democritus

Front

Which Quaker teacher challenged Aristotelian theory and showed that substances always break down into the same elements?

Back

John Dalton

Front

Who discovered the electron in 1897?

Back

J.J. Thompson

Front

What did J.J. Thompson's model of the atom propose?

Back

Atoms are uniformly packed spheres of positive matter filled with negatively charged electrons

Front

What did Ernest Rutherford's gold foil experiment reveal about atoms?

Back

Atoms consist largely of empty space with a dense, positively charged nucleus

Front

Who expanded on Rutherford's nuclear model and proposed that electrons orbit the nucleus at fixed energies and distances?

Back

Niels Bohr

Front

What did Werner Heisenberg's uncertainty principle state?

Back

It is impossible to determine both the exact position and speed of electrons

Front

What does the current quantum model of the atom propose?

Back

Electrons cannot be pinpointed but exist within a range of possible locations

Front

What happens when electrons circling an atom shift between energy levels?

Back

They absorb or release energy in the form of specific wavelengths of light

Front

What did Democritus propose about the nature of atoms?

Back

Atoms are made up of tiny particles surrounded by empty space