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Question

please help

describe the contributions to atomic theory made by the following scientist

a. dalton

b. thomson

c. milikan

d. rutherford

thank you :)

Answer 1

a. dalton - All elements are composed of indivisible particles. Atoms of the same element are exactly alike. Atoms of different elements are not alike. Compounds are formed by joining atoms of two or more elements

b. thomson - Said that the atom consists of positively charged protons and negatively charged electrons. Proved that an atom could be divided. Said the atom is neutral.

c. milliken -  Electrons - discovered by J.J. Thompson in 1897 using a cathode ray tube, mass = 1/1836 of a proton (negligible mass in determining atomic mass) was proven by Robert Milliken in 1909 using oil droplets in an electric field

d. rutherford - showed that the Atom has a nucleus, inside the nucleus are protons and neutrons, the nucleus&#039;s size can be compared to a bee in a stadium, outside the nucleus are the electrons in the electric cloud. Discovered this by shooting charged particles through a gold sheet and counting the number of particles that went through. Said the electrons orbit around the nucleus like the planets orbit around the sun

Answer 2

Dalton&#039;s Atomic Theory

1) All matter is made of atoms. Atoms are indivisible and indestructible.

2) All atoms of a given element are identical in mass and properties

3) Compounds are formed by a combination of two or more different kinds of atoms.

4) A chemical reaction is a rearrangement of atoms.

http://en.wikipedia.org/wiki/Atomic_theo...