Atomic Structure

Atomic Structure

1. Demoritus

   • Claimed that matter could not be divided into smaller pieces forever

2. John Dalton

   • Thought atoms are tiny solid ball, came up with atomic theory
     • In 1805, John Dalton published his atomic theory
       • All matter is made of tiny particles called atoms
       • Atoms are tiny hard spheres that cannot be broken down into smaller parts
       • Atoms cannot be created or destroyed
       • Atoms in an element always have the equal amount of protons and elctrons

3. J.J Thomson

   • Discovered electrons and also discovered atoms are made from positive and negative charged electrons

4. Rutherford

   • Discovered protons and nucleus. He called positive particles "protons" and the center of atoms the nucleus. He showed that atoms have positive particles in the center and mostly empty space.

5. Niels Bohr

   • Improved on Rutherford model and proposed that electrons move around the track around nucleus known as the shell.

6. Chadwick

   • Discovered particles with no charge and called it "Neutrons". Neutrons are also found in the nucleus.

7. The new atomic model has electrons moving around the nucleus in a cloud.

   • The overall diameter of an atom can be 100,000 times

8. Atoms are made up of electrons together with heavier subatomic particle called protons, electron and neutrons, these particles have very, very small masses and electric charges

9. The actual mass of a proton is 1.67*10 g

   • It is impossible to know where an electron is at any given time

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