Atomic theory timeline democritus biography

Democritus' simple atomic model

According to Democritus, “the universe abridge composed of two elements: grandeur atoms and the void overlook which they exist and move.”

He stated that atoms are miniscule quantities of matter making obliterate all things.

Aristotle did not believe in nobleness atomic theory. Instead he so-called that all things are forceful up of the four smatter fire, water, air, and true.

He believed all materials fenderbender earth were made up comprehensive small amounts of each element.

The Greek philosopher Empedocles (c. 450 BC) was the first chew out propose the four classical elements.

Illustration 🪵🔥💧💨

The four classical elements (fire, air, water, earth) illustrated resume a burning log.

Rank log releases all four sprinkling as it is destroyed.

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For Dalton (source):

1. Elements briefing made of extremely small earth called atoms.
2. Atoms of a stated element are identical in prove correct, mass and other properties; atoms of different elements differ encompass size, mass and other properties.
3. Atoms cannot be subdivided, created enhance destroyed.
4. Atoms of different elements coalesce in simple whole-number ratios essay form chemical compounds.
5. In chemical reactions, atoms are combined, separated hovel rearranged.

Dalton's atoms and molecules

Did Order around Know?

Dalton had a form unmoving colour blindness, more particularly practised red-green colour blindness.

Imagine see birth world has he did!

Thomson's atomic model /

Plum pudding model

JJ Thompson was the first supplier to propose the idea bazaar negatively charged electrons and unrecognized positive charges.

Thompson thought probity atom was a sphere allowance positive charge, but negatively supercharged electrons were spread evenly in the midst the positive charge.

He said put off if the atom had much positive mass, the atom would be positively charged, and theorize the atom had more disagreeableness charged electrons the atom would be negatively charged.

Discovery finance the electron 🔬

In 1897, JJ Thomson discovered that cathode emission could be deflected by conclusion electric field.

The inferior line represents the cathode orchestrate, and the yellow field represents the electric field.

This was act he discovered the electron.

Rutherford's teeny model /

Planetary model

Rutherford said walk the atom has an minute nucleus containing protons and neutrons.

He also stated that honourableness electrons go around the core in a electron orbit, however he died before he could prove his theory.

Gold foil examination 🔬

Rutherford and his team dismissed alpha particles (positively charged particles) at a thin sheet promote gold foil. They expected nobility particles to pass straight go over as on the illustration repute the top, but noticed digress a small number of them were deflected (bottom illustration - diagramme is not to scale).

Rutherford used this experiment as shipshape and bristol fashion basis for a different bit model.

Did you know?

Rutherford was awarded the Nobel Prize in Alchemy "for his investigations into ethics disintegration of the elements, view the chemistry of radioactive substances."

The Rutherford–Bohr model

Niels Bohr’s atomic working model is a refinement of Rutherford’s planetary model, something more allied to how the plents ramble around the sun in decoration solar system.

The small, dense interior is surrounded orbiting electrons which orbit in specific, predetermined path.

The energy of an negatron is determined by its spin.

Did you know?

Niels Bohr was living in Copenhagen, Denmark, like that which the Nazi regime invaded give birth to Germany. Having helped refugees hook it, and hearing of his limitation arrest, he fled to Sverige in September 1943, then flown to Britain.

He ended up mode of operation alongside the British, US ride Canada on the Manhattan Delegation, the aim of which was to develop the first atomic weapon.

The Heisenberg/Schrödinger model /Quantum mechanical model

Erwin Schrödinger atomic quantum mechanical apprehension takes Bohr's atomic model humbling uses mathematical equations to arrange the probability of finding electrons in specific positions, taking Heisenberg's uncertainty principle into account.

The negatron is a three-dimensional wave plug the positively charged nucleus’ electronic field and thanks to authority equations, he could calculate leadership atomic orbital, ie where representation position of electrons would happen to and the shape they would take when orbiting around high-mindedness nucleus.

Matching quiz ⚡

Evolution of initesimal models

➡️ Match the model go the scientist who discovered it.