Why is Dalton's work considered as the first atomic model?

Answer 1

What does it mean to "discover" something?

The first person to propose that matter was made

of atoms, and then write it down, was a Greek philosopher

named Democritus. But he had no experimental proof of his

notion. Then, a number of scientists, starting probably with Newton in

the late 1600s, proposed a corpuscular, or atomic, model. But it

wasn't until the late 1700s/early 1800s that John Dalton proposed

that all matter was made of atoms and actually used it to explain

a bunch of experiments that had been done on gases, and to calculate

atomic weights of elements. However, he still hadn't PROVED that

atoms existed...he just showed that the atomic concept was useful

and helped explain a lot of data. Probably the best direct probe

of the atom was first done by Rutherford and his student, C.T.R. Wilson,

who invented the cloud chamber and used it to show that when thin

gold foil is bombarded by helium nuclei (alpha particles), the particles

are occasionally deflected by a very large angle, but usually pass

straight through. This gave rise to the realization that the gold

was composed of atoms, with a tiny nucleus at the middle which

could occasionally collide with an alpha particle and send it flying.

-prof topper

His atomic model was first because, although Democritus proposed the atomic structure, he was the first person to record a model of the structure of the atom His atomic model was first because, although Democritus proposed the atomic structure, he was the first person to record a model of the structure of the atom