Discovery of an Atom (important people) Flashcards
what is an element?
simpilest form of matter
what are atoms?
smallest unit of an element which maintains all the properties of that element
most of an atom is ____________
empty space
what is the nucleus made up of & what charge does it have
positive charge, protons and neutrons
where do electrons exist? (3)
clouds, orbitals, energy levels
Mass of a proton, neutron, and electron & what is the unit its measured in?
proton- 1
neutron- 1
electron- “0”
atomic mass units
Elements are made of extremely small particles called atoms
John Dalton
discovered electron, charge and mass
JJ thomson
“Plum pudding”
solid substances with electrons sprinkled through out
JJ Thomson
Atoms of a given element are identical in size, mass, and other properties (Not always mass)
John Dalton
Atoms can be subdivided
JJ Thomson
Atoms cannot be subdivided, created, or destroyed (can be subdivided)
John Dalton
Discovered nucleus/proton, its charge and mass
Ernest Rutherford
Atoms of different elements combine simple whole number ratios to form chemical compounds
John Dalton
In chemical reactions, atoms are combined, separated, or rearranged
John Dalton
Proposed a tiny positive nucleus in the middle and empty space with electrons on the outside
Ernest Rutherford
discovered Bohr model of the atom; electrons move within certain energy levels/orbit around the nucleus
Niels Bohr
Discovered neutron; its charge and mass
James Chadwick
Added neutrons to the nucleus
James Chadwick
Discovered light can act as a particle (has matter) and a wave (energy)
Vincent de Brogile and Erwin Schrodinger
Explained random movements of the electrons/ ability to move energy levels
Vincent de Brogile and Erwin Schrodinger
Who gave us our current “electron cloud model”?
Vincent de Brogile and Erwin Schrodinger
what is energy?
the ability to do work
difference between a wave and particle
particle is matter & wave is energy
