chapter 2: quantum mechanical model of atom

quantum-mechanical model

probability of finding electrons within given orbitals or three-dimensional regions of space

electromagnetic radiation

radiant energy that includes radio waves, microwaves, visible light, x-rays, and gamma rays

amplitude

height of the wave

wavelength

distance between any two corresponding points on adjacent waves

frequency electromagnetic spectrum

number of events per unit of time that occur during regular intervals

gamma ray

form of high energy electromagnetic radiation, specifically photons, emitted from an excited atomic nucleus during radioactive decay or other nuclear reactions

x-ray

electromagnetic radiation with short wavelength and high energy

ultraviolet (UV) radiation

type of electromagnetic radiation with wavelengths shorter than visible light but longer than x-rays

visible light

range of electromagnetic radiation that can be detected by the human eye

infrared radiation

wavelength longer than visible light

microwave

wavelength from 1 millimeter to 1 meter

radio wave

long wavelength and low frequency

interference

two waves superimpose to form resultant wave of greater or lesser amplitude

constructive interference

peaks line up with peaks

destructive interference

out of phase interaction

diffraction

waves vend or spread out as they pass around edges of obstacles or through narrow openings

photoelectric effect

when light shone onto metal surface causes ejection of electrons from that metal

binding energy

energy required to separate a system of particles into its individual components

photon (quantum)

tiny particle that comprises waves of electromagnetic radiation

emission spectrum

unique pattern of light frequencies emitted by a substance when its electrons transition from higher to lower energy level

absorption spectrum

wavelengths absorbed by material

de broglie relation

mathematical relationship between particle’s wave function and its antiparticle’s wave function

complementary properties

pairs of properties that cannot be simultaneously known with perfect accuracy due to heisenberg uncertainty principle

heisenberg’s uncertainty principle

fundamentally impossible to know both exact position and momentum of particle simultaneously

deterministic

all facts and events are determined by external causes and follow natural laws

indeterminacy

inherent uncertainty or lack of determinacy in certain quantum mechanical properties of particles

orbital

describe location and energy of electrons in atoms

wave function

mathematical function that describes quantum state of an electron in an atom or molecule

quantum number

set of numbers that describes properties of atomic orbitals and electrons within them

principal quantum number (n)

describes energy level or shell of electron in atom

angular momentum quantum number (l)

determines shape of electrons orbital and its angular momentum in atom

magnetic quantum number (m_l)

spatial orientation of atomic orbital within subshell

spin quantum number (m_s)

intrinsic angular momentum

electron spin

spin about an axis

principal level (shell)

regions surrounding nucleus where atoms likely to be found

sublevel (subshell)

s, p, d, f

probability density

probability per volume

radial distribution function

probability of finding a particle at a certain distance from a reference particle

node

point in molecule where two or more atoms are connected

phase

region in substance throughout which all physical properties are essentially uniform