Atomic Theory In The Late 1800's

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An atom is made of a nucleus accommodating protons and neutrons (Atomic Structure Prezi). An atom is the particle that retains the properties of an element. Atoms are spherically shaped, mostly empty space, and are made up of three fundamental subatomic particles, the electron, proton, and neutron (Atomic Structure Prezi). Protons are of a positive charge, electrons are negatively charged and neutrons are neutral. Atomic theory is the theory that all matter is made up of tiny indivisible particles also known as atoms (Notes). In the late 1800’s a chemist and inventor named Dmitri Mendeleev published the very first version of the periodic table. The periodic table is a table of chemical elements that are arranged in order of atomic numbers…show more content…
James Dalton determined that elements exist as discrete packets of matter (Crash Course Video). Leucippus and Democritus composed the brilliant idea that all matter is composed of tiny uncuttable or “atomos” particles (Crash Course Video). There were many theories and discoveries on the knowledge of atoms in the past, some more known than others, like William Crookes (Crash Course Video and Atomic Structure Prezi). In the late 1800’s, Sir William Crookes discovered the Cathode Ray (Crash Course Video and Atomic Structure Prezi). While working in a darkened labratory one night he came across something he named the Cathode Ray. Cathode Rays are a stream of charged particles of which possess a negative charge. Scientists began probing what different subtances were made out of using discharge tubes (Crash Course Video). Discharge tubes are gas filled tubes that emanate light when an electrical current passes through. Scientists later found out that a positive charge was being emitted flowing in the opposite…show more content…
A series of Cathode Ray experiments were held to study the effects of both magnetic and electric fields. These experiments determined the ratio of its charge to its mass. He concluded that they weren’t rays but that they were very light, very small negatively charged particles aka corpulse or more commonly known as electrons (Crash Course Video). Thomson also concluded that the mass of the charged particle was less than the mass of a Hydrogen atom. This proved that there was a particle smaller than an atom. Thomson tried to answer questions about the nature of atoms using a model, this model was called the Plum Pudding Model (Atomic Structure Prazi). This model depicted the atom as a spherical shape composed of uniformly distributed positively charged electrons
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