first thought atom was a solid, indestructible, indivisible mass
solid; indestructible; indivisible
Democritus thought the atom was a ... , ... , ... mass.
said that the atomic model did not take into account electrons and protons
J.J. Thomson said that the atomic model did not take into account ... and ...
proposed that electrons surrounded a dense, positively charged nucleus and the rest of the atom was empty space
said that electrons were arranged in orbits around the nucleus
said that electrons in a particular path have a fixed energy
Niels Bohr said that electrons in a particular path have a ... ...
region around the nucleus where the electron is likely to be moving
Energy levels are more closely spaced the ... the distance from the nucleus.
the higher the energy level, the ... energy the electron has.
amount of energy required to move an electron from one energy level to the next higher one
an abrupt change of energy levels
quantum mechanical model
the present day atomic model
most probable location
The quantum mechanical model does not show paths, instead it shows the ... ... ... of an electron.
The denser the place in the cloud of the electron cloud model, the ... the probability of finding an electron.
came up with the mathematical equation showing energy and location of electron
Schrodinger came up with a mathematical equation showing the ... and ... of electron
principal quantum number
principal energy level or shell
number of ... is the same as the principal quantum number
regions within a sublevel where electrons can be found
maximum of ... electrons per orbital
lowest possible energy state
high energy systems are ...
ways in which electrons are arranged around the nucleus of atoms
electrons enter orbitals of lowest energy first
energy levels can ...
Pauli Exclusion Principle
for two electrons to occupy the same orbital, they must have opposite spins
two oppositely spinning electrons occupying the same orbital
before a second electron can be placed in any orbital, all orbitals of that sublevel must contain at least one electron
For neutral atoms, the sum of the superscripts is the number of ... in the atom.
outermost principal energy level of an atom that includes at least one electron
electrons in the valence shell
condition of an atom whose electrons are at higher energy levels than the ones they normally occupy