Why did JJ Thomson believe that electrons were present in the atom of all elements??

Answer 1

It was magnets…

Actually a simple observation. They had these really cool things called Crooks Tubes back in the day. Basically they were tubes much like a florescent light bulb (but clear), but these tubes also had a card inside them that was coated with a phosphor. When electrons hit the phosphor it glows. When high voltage was passed through the tubes a stream of electrons would flow from one side to the far side and the stream would glow. (its is pretty easy to see the flow of the stream).

Anyway Thompson was playing around with magnets and discovered that the negative pole repelled the stream of particles, and the positive pole attracted the stream. So he reasoned that the stream of particles was negatively charged. His buddy Robert Miliken worked out the charge and mass of the electron with his famous “oil drop” experiment.

Believe it or not one of our most advanced scientific instruments (the electron microscope) is based upon this same phosphorescent technology that Thompson was playing with over 100 years ago.

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

http://en.wikipedia.org/wiki/Oil-drop_experiment

Answer 2

the electron is least huge, it has almost no mass on a similar time as the two protons and neutrons weigh some million AMU. Atomic variety, mass numbers variety with isotopes. Nucleus, that's made up of protons and neutrons. electron clouds comprise maximum *quantity* yet very almost not one of the mass. sixteen, sulfer 34 is an isotope that isn't regulate the type of electrons. electrons = proton (i.e. atomic variety) till it is an ion. it under is going nuclear fission,fusion or decay, whether (in case you haven't any longer gotten to that stuff) whilst electrons shift up a point, this releases a photon i.e. particle of light. Atomic variety is the type of protons interior the atom, the Mass variety is the blended type of protons and neutrons the atom has 11 electrons. the atomic variety is the type of protons interior the atom and the type of electron *continuously* equals the type of protons till it is an ion with a polar fee.