Chapter 4 Flashcards
Democritus
thought you would eventually end up with a particle that could not be cut
Dalton
developed his atomic theory from observations gathered from many experiments
Thomson
proposed that electrons were located throughout an atom like plums in a pudding, as shown in this model
Rutherford
proposed that in the center of the atom is a tiny positively charged part called the nucleus
Bohr
proposed that electrons move around the nucleus in certain paths, or energy levels
Atom
the smallest unit of an element that maintains the properties of that element
Electron
a subatomic particle that has a negative charge
Nucleus
in physical science, an atom’s central region, which is made up of protons and neutrons
Electron Cloud
a region around the nucleus of an atom where electrons are likely to be found
Proton
a subatomic particle that has a positive charge and that is found in the nucleus of an atom
Atomic Mass Unit
a unit of mass that describes the mass of an atom or molecule
Neutron
a subatomic particle that has no charge and that is found in the nucleus of an atom
Atomic Number
the number of protons in the nucleus of an atom; the atomic number is the same for all atoms of an element
Isotope
an atom that has the same number of protons (or the same number atomic number) as other atoms of the same element do but that has a different number of neutrons (and thus a different atomic mass)
Mass Number
the sum of the numbers of protons and neutrons in the nucleus of an atom
