unit 3 - periodic properties Flashcards
wavelength
distance between two peaks or troughs in a wave
waves
oscillation of a property over time or space; can transport energy from one point to another
frequency
number of wave cycles that pass a specified point in space per unit time
photoelectric effect
when light shines on a metal, electrons are ejected from the surface of the metal
photon
particle of light
line spectra
electromagnetic radiation emitted at discrete wavelengths by a specific atom in the excited state
Bohr model
each electron moves around the nucleus in circular orbits, each with a specific radius
heisenberg uncertainty principle
rule stating that it is impossible to determine both the momentum and position of a particle at the same time;
the uncertainty principle is a consequence of quantum particles exhibiting wave-particle duality
quantum number n
determines the size of the orbital;
must be equal to or greater than 1
quantum number l
determines the shape of an orbital sublevel;
an s orbital is marked by l = 0;
must be any number from 0 - (n - 1)
quantum number ml
defines the orientation of the orbital in space
can be any number from -L to L
quantum number ms
spin number; determines the direction the electron spins
can be -1/2 or 1/2
degenerate orbitals
orbitals that have the same energy (n)
pauli exclusion principle
no two electrons will ever have the same four quantum numbers
electron configuration
listing that identifies the electron occupancy of an atom’s shells and subshells
ground state
state in which the electrons in an atom, ion or molecule have the lowest energy level possible
excited state
state in which electrons have gained some energy and possess more energy than in the ground state
periodic table
a chart where elements are sorted by their atomic number
metals
element that is shiny, malleable and conducts heat and electricity
metalloid
element that possesses some properties of metals and some properties of nonmetals
nonmetals
element that appears dull and conducts heat and electricity poorly
main groups
elements in groups 1-3 and 13-18
transition metals
elements in groups 3-12
inner transition metals
elements on the bottom rows of the periodic table;
valence electrons
the outermost electrons of an atom
hund’s rule
every orbital in a subshell is occupied with one electron before any orbitals can be doubly occupied. all electrons in singly occupied orbitals have the same spin number / ms
E = hv = (hc/λ)
Energy of a photon / radiation, where
- λ is in m
- h = (6.626 x 10^-34)
c = λv
speed of light relating to wavelength and frequency
1/λ = k(1/nf^2 - 1/ni^2)
used to find wavelengths of light emitted by hydrogen atoms
E = (-kZ^2) / n^2
energy of an orbit in a hydrogen atom
hc/λ = k(1/nf^2 - 1/ni^2) = ^E
An alternative expression for energy absorbed/emitted upon moving orbits
covalent radius
1/2 the distance between the nuclei of two identical atoms when they are joined by a covalent bond
ionization energy
energy required to remove an electron from a gaseous atom or ion
effective nuclear charge
charge that leads to the coulomb force exerted by the nucleus on an electron;
nuclear charge - shielding;
increases across a period, decreases down a group
shielding
the probability of another electron being between the electron of interest and the nucleus
