chapter 4 Flashcards
the smallest unit of an element that maintains the properties of that element
atom
a subatomic particle that has a negative charge
electron
in physical science, an atom’s central region, which is made up of protons and neutrons
nucleus
a region around the nucleus of an atom where electrons are likely to be found
electron cloud
a subatomic particle that has a positive charge and that is found in the nucleus of an atom
proton
a unit of mass that describes the mass of an atom or molecule
atomic mass unit
a subatomic particle that has no charge and that is found in the nucleus of an atom
neutron
the number of protons in the nucleus of an atom; the atomic number is the same for all atoms of an atom
atomic number
an atom that has the same number of protons as other atoms of the same element do but that has a different number of neutrons.
isotope
the sum of the numbers of protons and neutrons in the nucleus of an atom
mass number
the mass of an atom expressed in atomic mass units
atomic mass
What theory did John Dalton discover?
John Dalton developed that all matter is made up of atoms
What was Aristotle’s theory?
He believed that you would never end up with a particle that could not be cut
What theory did Thomson discover?
The plum pudding model
What experiment did Rutherford discover?
positively charged particles
