Test Review Flashcards
What are two regions of an atom
nucleus and electron cloud
what are the three basic components of an atom
Protons, Neutrons, Electrons
how does the nucleus compare to the rest of the atom
it is 10k times larger
what is the scanning and tunneling electron microscope (STM used for
it provides 2D and 3D images of atoms
what holds electrons and the nucleus together
electric charge
unlike charges _________, like charges _________
attract, repel
charges on an electron are
negative
charges on a proton are
positive
charges on a neutron are
neutral
why is the overall charge of an atom neutral
of protons = # of electrons
when two atoms meet, what parts of the atoms interact
the electrons
what are some ways that signals from the atom can be used
they are used to determine the # and type of atoms
democritus
coined the term atom
john dalton
- first atomic theory
atoms are indivisible, atoms of the same element are alike, all elements are composed of atoms
JJ thompson
- plum pudding model
discovered the electron and proved the atom to be divisible
Rutherford
discovered the nucleus of an atom with gold foil experiment
Niels Bohr
electrons move in definite orbits around the nucleus
Robert Millikan
calculated a more accurate value for charge and mass of electrons
Goldstein
discovered protons
James Chadwick
discovered neutrons
Atomic # is a _____ number
whole
mass # = ?
of neutrons + # of protons (round off decimal)
atomic mass
weighted average of an atoms isotopes
isotope
atoms of the same element that differs in the # that changes the mass
calculating mass of an element
multiply amu by percent (move decimal 2 places to the left)
add up all results
protons are found where
in the nucleus
the # of protons in the nucleus is called the
atomic #
how are isotopes of an element alike and different
same element type but different masses
3 conclusions of rutherfords expriment
- electrons surround the nucleus
- atoms contain empty space
- atoms repel
