Chapter 2 Review Flashcards
wavelength (λ)
distance between two peaks or troughs in a wave
frequency (v)
points to the number of waves (cycles) per second that pass a given point in space
speed (c)
the speed of light (c) = 2.9979 x 10^8 m/s
Inverse relation with λ and v
All electromagnetic radiation travel with speed of light, c, short-wavelength radiation must have a high frequency
λv = c
Planck’s constant
6.626 x 10^-34 J/s
quantized energy
energy can occur in discrete packets, or quanta
Finding quantum of energy
Delta * E = hv
Energy of photons
E = hv = (hc/λ)
photoelectric effect
when v < v-subzero, no electrons are emitted regardless of the intensity of light
when v > v-subzero, the number of electrons increases with light intensity
when v > v-subzero, the kinetic energy of emitted electrons increase linearly with the light frequency
photoelectric equation
KE = (1/2)mv^2 = hv -hv-subzero
Theory of relativity
E = mc^2
Energy has mass
De Brogile’s equation
Calculates the wavelength of a particle
λ = h / mv
diffraction
the result of light scattering
scattered light
can interfere constructively, producing a bright area
can interfere destructively to produce dark spots
continuous spectrum
when white light is passed through a prism, contains all wavelengths that are visible to the human eye
Line spectrum
hydrogen emission spectrum, displays only a few lines, with each line corresponding to discrete wavelengths
indicates the energy of the electron on the hydrogen atom is quantized
standing waves
stationary waves that do not travel along any length
only certain orbits have a circumference into which whole number wavelengths of standing electron waves will fit
other waves produce destructive interference of the standing electron wave
wave function
a function of the coordinates of the electron’s position in 3D space
Dual nature of light
Light exhibits both wave properties and particle properties
probability distribution
indicates the probability of finding an electron near a particular point in space
radial probability distribution
plots the total probability of finding an electron in each spherical shell versus the distance from the nucleus
(can also be interpreted as a cross section of a given orbital)
Atomic Theory
Atoms of a given element are identical, and different atoms of different elements are therefore different.
Compounds are formed when atoms of different elements combine with each other.
A given compound always has the same relative numbers and types of atoms.
Composition of the atom
Protons: Found in the nucleus, has a positive charge. Charge is equal in magnitude to the electron’s charge.
Electrons: Found outside of the nucleus, is negatively charged
Neutrons: Found inside the nucleus, virtually the same mass of a proton. No charge
Isotopes
Atoms with the same number of protons but different numbers of neutrons are isotopes
