Chemistry: History of The Atom

Democritus

FIRST ATOM THEORY Proposed the theory that everything is made of atoms (indestructible units with space in betweens them).

John Dalton

A scientist who formulated the MODERN ATOMIC THEORY, proposing that all matter is composed of atoms and that atoms of a given element are identical.

Dalton Model of the Atom

A solid sphere shaped like a “billiard ball”.

J. J. Thomson

Experimented with CATHODE RAY TUBES and discovered the negatively charged particles (elections) DISCOVERED ELECTRONS

Thomson: Plum Pudding - Negative electrons floating in a positive region, founded from cathode ray tubes.

Ernest Rutherford

GOLD FOIL Experiment : shot positively charged alpha particles at a thin sheet of foil in which the particles deflected instead of passing through the foil.

RUTHERFORD Model of the Atom: Dense positively charged center (nucleus) that electrons float around.

Niels Bohr

Danish scientists who modified Rutherford’s model w/ behavior of electrons. ELECTIONS ORBIT THE NUCLEUS on specific paths.

Bohr Model of the Atom (BOHR for ORbit yeahhhhhhh?)

James Chadwick

Discovered the NEUTRON - Experimented w/ Radiation and discovered that the nucleus contained NEUTRONS AND PROTONS TOGETHER. (pft this is boring his name has no correlation to what he did, not even a single letter.)

Chadwick Model of the Atom

Erwin Schrodinger

Claimed that the exact location of electrons in an atom could COULD NEVER BE KNOWN. Theorized the ELECTRON CLOUD. This is the most current thought/theory. (Erwin as in wind as in the wind in the clouds as in electron clouds ayyyyyy)

Dobereiner

Arranged the FIRST PERIODIC TABLE in TRIADS by similar properties. (He was the first one and he triad… tried, triad, get it??)

Dmitri Mendeleev

Organized the 63 elements by ATOMIC MASS and left GAPS for elements that had not been discovered. (Dmitri with the m for Mass and Mende”leev” like he leaves spaces for elements. Ahhhh you see it you see it.)

Henry Moseley

THIS IS NOW THE MODERN PERIODIC TABLE. Organised periodic table by atomic number (like the N in his name for Number) to help define elements. Grouping of elements with similar properties.