test 2 Flashcards
gold foil experiment
nucleus is small and dense and its mostly empty space. Alpha particles were shot at gold foil and some went through while others bounced back
solar system model
electrons orbit the nucleus at constant speeds causing them to implode,
electron cloud model
electrons travel randomly and occupy energy levels based on the 90% probability of finding an electron in empty space called quantum mechanical model
wave-particle duality of motion
electrons act like both waves and particles
electromagnetc radiation
energy lost or gained when electrons move energy levels
Electromagnetic spectrum
Consists of radiation over a broad range of wavelengths
amplitude
the height of the wave from origin to crest
wavelength
the distance between wave crests units in cm
frequency
number of wave cycles to pass a given point per unit of time. units are v or Hz
inversely proportional
when one goes up the other goes down
speed of light in a vaccum
3.00x10^8 m/sec formula is c=wavelengthv
photoelectric effect
electrons are ejected by metals when light shines on them, lightwaves act like particles. the energy of the light has be at a certain minimum energy
quantum concept
energy increases in small discrete units called quanta
photon
discrete units of light energy
frequency 2
energy per photon
intensity
number of photons
planks constant
h=6.626x10⁻34J*sec
Formula to find energy
E=hv
Atomic Emission Spectra
every element emits a unique atomic spectrum the pattern of frequencies obtained by passing energy emitted by atoms of an element in the gas phase through a prism
ground state
the lowest energy level
excited state
highest energy level an electron can be
valance electron
in the outermost shell they determine how an atom will react
octet rule
atoms having 8 electrons in the valance shell it determines the physical and chemical properties
protons and electrons same as
atomic number
cations
metals that lose electrons to become positive
anions
nonmetals that gain electrons and become negative
atoms are
neutral & unstable
ions are
charged & stable
protons determine what
which element it is, its an identifier
decimals on the PT?
Weighted average mass of all the isotopes
shortest to longest
violet, indigo, blue, green, yellow,orange, red
evidence for particle theory of electron
planks quantum model and the photoelectric effect
whys the sky blue?
Blue light has a shorter wavelength so it travels faster and spreads farther and the white light passes through the atmosphere and air molecules cause it to scatter
crest
top of wave
trough
botttom of wave
mid point
middle of a wave
