III. Atomic Theory Flashcards
Atom
The smallest particle of matter
Element
Things composed of a single type of atom
Molecule
Groups of two or more atoms that are linked by
chemical bonds to form distinct units
Diatonic elements
Elements that exist as molecules composed of two atoms
Elements that exist as larger molecules
Phosphorus, Sulfur
Atomic Theory
A scientific concept that explains the nature of matter
and its behavior
Democritus
Ancient Greek philosopher that proposed Atomic Theory 01
What did Democritus call these particles?
“Atomos” - Greek for “indivisible” or “uncut”
When did Democritus propose Atomic Theory 01?
400 B.C.
Who made the Solid Sphere Model of the Atom?
John Dalton
When did John Dalton propose the Solid Sphere Model of the Atom?
1803
Who used electricity to
decompose chemical compounds?
Humphry Davy and Michael Faraday
Who proposed that units of electrical charge - negatively charged particles - were associated with atoms, and named them “electrons” (Greek “elektron”, which means “amber”)?
George Stoney
Who proposed that the atom is composed of a positively charged sphere with negatively charged electrons distributed throughout it?
J.J. Thompson
What did J.J. Thompson propose?
Plum Pudding / Raisin Bread Model
When did J.J. Thompson propose the Plum Pudding/Raisin Bread Model?
1904
Who along with J.J. Thomson’s further works led to the discovery of positively-charged particles, named protons?
Wilhelm Wien
Who showed that proton is a component of all matter?
Ernest Rutherford
Whose experiment disproved the Plum-Pudding Model?
Hans Geiger, and an assistant, Ernest Marsden
Who proposed that most of the mass of the atom is concentrated in a tiny, positively charged nucleus at the center, with negatively charged electrons orbiting around it?
Ernest Rutherford
Who proposed the Nuclear Model/Planetary Model?
Ernest Rutherford
What did Ernest Rutherford propose?
Nuclear Model/Planetary Model
When did Ernest Rutherford propose the Nuclear Model/Planetary Model?
1911
What is an atom mostly?
Empty space
What is at the center of the atom?
Nucleus
What does the nucleus contain?
Protons and Neutrons
What is the charge of Protons?
Positive
What is the nucleus surrounded by?
Electrons
How many electrons surround the nucleus?
As many as there are protons in the nucleus
What is uncharged/contains no charge?
Neutrons
What is the charge of Electrons?
Negative
