Question

Discovery of atom explai...​

Answer 1

Democritus was an important philosopher. However, he was less influential than the Greek philosopher Aristotle, who lived about 100 years after Democritus. Aristotle rejected Democritus’s idea of atoms. In fact, Aristotle thought the idea of atoms was ridiculous. Unfortunately, Aristotle’s ideas were accepted for more than 2000 years. During that time, Democritus’s ideas were more or less forgotten.

Dalton Brings Back the Atom

Around 1800, a British chemist named John Dalton revived Democritus’s early ideas about the atom. Dalton is pictured in Figure below. He made a living by teaching and just did research in his spare time. Nonetheless, from his research results, he developed one of the most important theories in science.

.Dalton's Research

Dalton did many experiments that provided evidence for atoms. For example, he studied the pressure of gases. He concluded that gases must consist of tiny particles in constant motion. Dalton also researched the properties of compounds. He showed that a compound always consists of the same elements in the same ratio. On the other hand, different compounds always consist of different elements or ratios. This can happen, Dalton reasoned, only if elements are made of tiny particles that can combine in an endless variety of ways. From his research, Dalton developed a theory of the atom

Dalton's Atomic Theory

The atomic theory Dalton developed consists of three ideas:

All substances are made of atoms. Atoms are the smallest particles of matter. They cannot be divided into smaller particles. They also cannot be created or destroyed.

All atoms of the same element are alike and have the same mass. Atoms of different elements are different and have different masses.

Atoms join together to form compounds. A given compound always consists of the same kinds of atoms in the same ratio.

Dalton’s theory was soon widely accepted. Most of it is still accepted today. The only part that is no longer accepted is his idea that atoms are the smallest particles. Scientists now know that atoms consist of even smaller particles.

Dalton's Atomic Models

Dalton incorrectly thought that atoms are tiny solid particles of matter. He used solid wooden balls to model them. The sketch in the Figure below shows how Dalton’s model atoms looked. He made holes in the balls so they could be joined together with hooks. In this way, the balls could be used to model compounds. When later scientists discovered subatomic particles (particles smaller than the atom itself), they realized that Dalton’s models were too simple. They didn’t show that atoms consist of even smaller particles. Models including these smaller particles were later developed.

Answer 2

one of the Greek philosopher introduced the idea if an atom he proposed the structure of atom he said that the any solid when goes on dividing comes to a smallest particle called atom .....

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