Science U 3 L1 Flashcards
smallest particle into which an element can be divided and still be the same element
atom
what was the difference between Dalton’s theory and the ideas of Democritus and Aristotle
His theory was based on evidence
Who’s theory states that all matter is made up of atoms?
John Dalton
Whos thought that atoms cannot be created, divided or destroyed?
John Dalton
Theory stated that all atoms of a certain element are identical but atoms of different elements are different from each other
John Dalton
Believed that atoms join with other atoms to make new substances
Joh Dalton
Experiments provided evidence that atoms are made up of even smaller particles within the atom that have a negative charge known as electrons
JJ Thompson
Experiment suggested that atoms have a nucleus with positive charge (protons)
Ernest Rutherford
Believed that electrons move around the nucleus in circular paths that are a certain distance from the nucleus.
Niels Bohr
Atomic Theory
atoms are the basic unit of matter and that the atoms of each element are unique, atoms are made up of electrons and protons
Discovered that the nucleus contains uncharged particles called nurtrons
James Chadwick
Discovered that electrons move within an area around the nucleus called the electron cloud
James Chadwick
electrons move within an area around the nucleus called what?
electron cloud
atomic number
number of protons in the nucleus of an atom
mass number
total number of protons and neutrons in an atoms nucleus
