honors chem atomic model

Aristotle

Everything was made of four elements, fire, water, earth and air

Democrtius

hypothesized atoms, uncuttable bits that hooked together, no one believes him cause the influence of aristotle is too strong

Antoine Lavioser

Carried out experiments where he carefully weighed out reactants before and after and saw that the mass was conserved

Dalton's Atomic theory

All matter is composed of tiny indivisible particles called atoms. Atoms of the same element are alike, atoms of different elements are different. Compounds are formed when different elements combine in fixed proportions. Chemical reactions rearrange, nothing is created or destroyed

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his indivisible thing is wrong, atoms can be broken up even smaller

Problems with Daltons Theory

Only showed the atom, did not show what's inside nor explained charges

Thompson models

Shell of a positive charge, with negatively charged electrons inside of it

Cathode Ray Experiment

JJ Thompson used a cathode ray, and emitted electrons from an cathode to an anode. He put a positive plate on top and a negative plate on the bottom, it was deflected upwards towards the positive plate, so the electrons were negative. 

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Millkan

Did his oil drop experiment, which added on to JJ Thompsons plum pudding model, found the mass and charge of electrons

Millkan Oil Drop Experiment

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experiment where he sprayed oil droplets, and balanced the force of gravity with charge to suspend the air. he did this in an electric field where electrons charged up the oil. Observing this, he calculated the mass and charge of an electron.

Alpha Particle

positively charged particles

Rutherfords Gold Experiment

He shot alpha particles at a gold foil, and then had a detector around it. Most of it went right through the foil, and some bounced back, because it hit something inside the atoms of the foil, which is the nucleus. Alpha particlkes are positivley charged, so it hit some positive charged thing and repelled, which is the nucleus. He also proposed electrons orbit around the nucleus, as if it stayed still it would collapse into the nucelus, but if it orbited around it, it would stay oribting via centrifugal force

Rutherford atomic Model

Atom is mostly empty space, but there is a positively charged nucleus in the center with positively charged protons inside, electrons scattered

Problems with rutherford

If there are positive nucleus, and positive protons, they should repel cause like charges repel, so there must be something else Also charged particles that move around infinitly are going to lose energy and stop

Chadwick

Mass of atom does not equal mass of protons, something else. Used this using atomic model, discovered neutrons were neutral charge and the same size and weight as protons so it could move it around. 

Atomic line emission spectrum

When voltage is applied and the atoms absorb energy it becomes excited, excited atoms emit energy as light  Energy varies, color varies

Planetary Model

Bohr discovered electrons orbit around the nucleus in fixed energy orbits, in different level, chadwick added on because he had no nucleus, orbit using electromagnetic force

Excited state

atoms must absorb energy to go from a lower energy level to higher

Ground state

energy becomes emitted and goes to a lower energy level

Continuous

classical physics, when its like a smooth ramp, no set amount of energy to go up the ramp.

Discontinuous

energy is like steps, you need a certain amount of energy to go up the steps, if you dont have enough you cant go up