chemistry - module 4

electromagnetic radiation

electromagnetic radiation

form of energy that exhibits wavelike behavior as it travels through space

λ

wavelength

v

frequency

c

speed of light

wavelength

shortest distance between equivalent points on a continuous wave (centimeters, nanometers, meters)

frequency

number of waves that pass a given point per second, (1/s, Hz)

amplitude

wave’s height from origin to crest

3.00×10 e8

speed of light ( c )

longer wavelength

lower frequency

shorter wavelength

higher frequency

electromagnetic spectrum

includes all forms of electromagnetic radiation

quantum

the minimum amount of energy that can be gained or lost by an atom

planck’s constant

6.626×10 e-34 Jxs, shows that the energy of radiation increases as the radiations frequency increases

photoelectric effect

electrons are emitted from a metal’s surface when light shines on it

photon

massless particle that carries quantum energy

atomic emission spectrum

set of frequencies of the electromagnetic waves emitted by atoms of the element

Bohr Model

correctly predicted the frequencies of the lines in hydrogen’s emission spectrum

ground state

lowest allowable energy state

excited state

energetic state of an atom

quantum number

number assigned to each orbit of an electron

electron in n=1

when a hydrogen atom is in a ground state (first energy level)

the bohr model failed to explain

the spectrum of any other element, did not fully account for the chemical behavior in atomsLo

Louis de Broglie

proposed a new idea on how atoms are arranged (orbits are like waves), the bohr model was incorrect

deBroglie equation

lambda = h/mv

Werner Heisenburg

proved to have found profound implications for atomic models, showed that it is impossible to measure an object without tampering with it

Heisenburg uncertainty principle

states that it is impossible to know precisely velocity and position of a particle at the same time, it is only known for certain the area in which an electron occupies around the nucleus

Erwin Schrodinger

derived an equation that treated the hydrogen’s atom as a wave

quantum mechanical model of the atom

atomic model in which the electrons are treated as waves

atomic orbital

probability of an atom residing in a specific area or region

electron configuration

arrangement of electrons in an atom

aufbau principle

states that each electron occupies the lowest energy level available

Pauli exclusion principal

states that a maximum of 2 electrons can occupy a single atomic orbital, only if they have opposite spins

Hund’s rule

single electrons with the same spin must occupy the equal energy orbital before other different spin electrons can occupy the orbital

valence electrons

electron’s in the outermost orbitals