1. The electron was discovered by J.J. Thomson in 1897.
2. Democritus concluded from his theory of the universe that all matter is composed of tiny, indivisible particles called atoms.
3. The subatomic particles are the particles that make up atoms, including protons, neutrons, and electrons.
4. The planetary model of the atom was proposed by Niels Bohr in 1913, building on the earlier work of Ernest Rutherford, who discovered the atomic nucleus.
5. John Dalton's Atomic Model concluded that all matter is made up of atoms, which are indivisible and indestructible. He also proposed that atoms of different elements have different masses and that chemical reactions involve the combination, separation, or rearrangement of atoms.
Answers & Comments
Answer:
1. The electron was discovered by J.J. Thomson in 1897.
2. Democritus concluded from his theory of the universe that all matter is composed of tiny, indivisible particles called atoms.
3. The subatomic particles are the particles that make up atoms, including protons, neutrons, and electrons.
4. The planetary model of the atom was proposed by Niels Bohr in 1913, building on the earlier work of Ernest Rutherford, who discovered the atomic nucleus.
5. John Dalton's Atomic Model concluded that all matter is made up of atoms, which are indivisible and indestructible. He also proposed that atoms of different elements have different masses and that chemical reactions involve the combination, separation, or rearrangement of atoms.