what is the quantum-mechanical model?
- -energy of electrons is quantitized. (electrons can only have a specific amount of energy.
- - electrons exhibit wavelike behavior.
- -it is impossible to know the exact position as well as the momentum of an electron at any given instant.
regions of ihgh probablity have ___ electron density.
low probablity have ___ electron density
a region around the nucleus of an atom where an electron is found.
what do orbitals have?
what can't they do?
shapes, sizes and energies.
cannot describe how the electron moves.
orbitals are designated by which letters?
s, p, d, and f
what shape does the orbital s take
d and f?
who proposed that the energies of the electrons in an atom are quantinized?
what does n stand for?
the principal quantum number
when n increases, what else increases?
the energy of the electron
the number of sublevels always equal...
the quantum nmber n.
n = 4; 4 sublevels
what type of number is the orbitals in each sublevel?
- 1 orbital in s sublevel
- 3 orbital in p sublevel
- 5 orbital in d sublevel
- 7 orbital in f sublevel
do the electrons spend more time further away from the nucleus or nearer?
how many number of orbitals and max. # of electrons are found in the sublevels s, p, d, and f?
- s - 1 orbital - 2 max electrons
- p - 3 - 6
- d- 5 - 10
- f- 7- 14
what is electron configuration?
distribution of electrons among the orbital of an atom
how is the electron configurations of atoms determined?
distributing the atom's electrons among level, sublevel and orbitals.
when electrons populate the lowest energy orbitals available, the atom is in...
what is the ground state?
lowest, most stable state of the atom
how can the locatioin of the lectrons in the ground state be predicted?
using the aufbau prinicple, the pauli exclusion principle and Hund's rule
what is the aufbau (german: building up) principle?
electrons are added one at a time to the lowest energy orbitals.
what is the pauli exclusion principle?
an orbital can hold a max. of 2 electrons. Must spin oposite directions.
what is Hund's rule?
electrons occupy equal-energy orbitals so that a max. number of unpaired results.
higher energy orbital means that the atom is in an ____ state
excited state (unstable state)
which elements are exceptions with the Aufbau principle?
Chromium and Copper
why do expectations to the Aufbau principle occus?
it is due to the subtle electron electron interactions in orbitals with similar energies.