Atomic Structure Flashcards
atomic number (Z)
number of protons
mass number (A)
protons + neutrons
valence electrons
- electrons farthest from the nucleus
- determine reactivity of an atom
mole
- unit used to count particles
- represented by avagadro’s number
avagadro’s number
6.022 x 10^23 particles
isotopes
multiple species of atoms with the same number of protons but different number of neutrons
energy value of a quantum
E=hf
-h=6.626 x 10^-34 (planck’s constant)
ground state
electrons in its lowest energy state
electromagnetic energy of photons emitted when electrons return to ground state
E = hc/lamda =hf
Pauli exclusion principle
no 2 electrons in a given atom can possess the same set of 4 quantum numbers
principal quantum number (n)
- the larger the integer the higher the energy level
- difference in energy between adjacent cells decreases as the distance from the nucleus increases
maximum number of electrons in energy level n (electron shell n)
2n^2
azimuthal quantum number (l)
- subshells that occur within each principle energy level
- can be any integer in the range of 0 to n-1
- 4 subshells corresponding to l=0, 1, 2, 3 are s, p, d, f
maximum number of electrons that can exist within a subshell
4l + 2
magnetic quantum number (ml)
- the particular orbital within a subshell where an electron is highly likely to be found at a given point in time
- all integers from -l to l including 0
spin quantum number (ms)
- the spin of a particle
- +1/2 or -1/2
- whenever 2 electrons are in the same orbital they must have different spins
(n + l) rule
the lower the values of the sum of the first and second quantum numbers, the lower the energy of the subshell
Plancks Theory
the energy wave is:
- directly related to frequency
- indirectly related to wavelength
- directly related to its absorption spectrum
- directly related to its emission spectrum
paramagnetic species
- weakly attracted to magnetic field
- unpaired electrons
diamagnetic species
- not affected by magnetic field (slightly repelled)
- unpaired electrons
comparing atomic radius of molecules with the same number of electrons
the molecule with more protons has a smaller atomic radius because there will be more pull toward the nucleus
number of orbitals in a subshell
2l + 1
