Unit 4 (chapter 11) Flashcards
Amplitude
height of a wave, same from baseline to trough or crest, the higher the wave, the greater the intensity of light
atomic line spectrum/bright line spectrum
“fingerprint of element”, colors that are emitted from element
aufbau principle
electrons are “built up” in an atom from orbitals of lowest energy to orbitals of highest energy, ground state configuration
continuous
going on without stopping
core electrons
the electrons in the inner shells of an atom; these electrons are not involved in forming bonds (all electrons that aren’t valence electrons)
Electromagnetic radiation
form of energy that exhibits wavelike behavior as it travels through space, moves at speed of light
electron configuration
shorthand designation of the number of electrons in each subshell
electron spin
a property of the electron that makes it behave as though it were a tiny magnet. The electron behaves as if it were spinning on its axis; electron spin is quantized. Two electrons must spin in opposite directions
excited state
when an atom absorbs energy, its electrons move to a higher energy level, as higher potential energy than in ground state
frequency
the number of waves that pass a fixed point per unit of time. Measured in cycles per second (Hz) (v “nu”)
ground state
the lowest energy state of an atom
hund’s rule
when there is more than one orbital in the same subshell, electrons do not pair until all orbitals of the same energy have 1 electron “the buffet rule”
orbital
a representation of the space occupied by an electron in an atom; the probability distribution for the electron
Orbital diagram
Uses lines or boxes to indicate orbitals and arrows to indicate electrons
Pauli Exclusion Principle
Two electrons in the same orbital must have opposite spins, only two can fit in one orbital
Photoelectric effect
refers to the emission of electrons from a metal when light shines on the metal, einstein
Photon
A particle of electromagnetic radiation with no mass that carries a quantum of energy
Quantized
electrons can only exist at specific energy levels, separated by specific intervals
quantum (plural, quanta)
the precise amount of energy possessed by a photon; the difference in energy between two atomic orbitals
Quantum number
the number assigned to each orbit of an electron (n)
Shell or energy level
quantized regions of increasing energy (around the nucleus) in which orbitals can be found
Subshell or sublevel
s, p, d, f
Valence electrons
Electrons on the outermost energy level of an atom
Wavelength
Distance between similar points on 2 consecutive waves
Wave mechanical model/quantum model
Modern model of the atom, atoms have electrons in “orbitals” that are like clouds around the nucleus
Bohr’s model
Electrons are in energy levels orbiting nucleus, electrons have specific amounts of energy determined by their distance from the nucleus, evidence for this model includes line emission spectrum of hydrogen, electrons can move from one energy level to the next
de Broglie
Scientist who suggested that all moving particles had a wave motion associated with them, proposed that light could as a wave and particle, electrons could act as standing waves therefore only certain wavelengths could fit
Problems with Bohr’s model
Only works with H, fails to explain shape of molecules and chemical bonding
Schrodinger
- Quantum Mechanical Model of Atom - uses probability in determining the location of electron but there are still places it can’t be
Quantum model
Electrons are in orbitals within sublevels within energy levels, orbitals are regions where electrons have a 90% of being, electrons act as waves and particles, uses Schroedinger’s wave equation to predict where electrons may be, most modern model of atom (currently accepted model), electrons have specific amounts of energy determined their distance from the nucleus, electrons position can be represented by orbital diagram or electron configuration
Heisenberg uncertainty principle
It is impossible to know the position of a particle and the velocity of the particle with certainty at the exact time
electromagnetic spectrum
radio waves, microwaves, infrared waves, visible light, ultraviolet waves, x rays, and gamma rays
Dark bands of hydrogen spectrum
energy not given off
Bright lines of hydrogen spectrum
correspond to photons released
wavelength unit
meters (m)
frequency unit
Hertz (Hz)
Planck’s constant unit
J x s
Energy unit
Joules (J)
relationship between wavelength and frequency
inverse
Relationship between wavelength and energy
inverse
Relationship between frequency and energy
direct
the original nuclear model of the atom developed after the gold foil experiment in which some alpha particles rebounded at larges angles…
…does not account for the stability of the atom since accelerating electrons would not lose energy and fall into the nucleus
