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44 Cards in this Set
- Front
- Back
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Electromagnetic Radiation
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Form of energy that exhibits wavelike behavior as it travels through space
ex: visible light, microwaves, x-rays |
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What three characteristics are all waves described by?
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1. wavelength
2. frequency 3. amplitude |
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Wavelength
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Shortest distance between equivalent points on a continuous wave
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Frequency
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Number of waves that pass a given point per second
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Amplitude
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Wave's height from origin to crest
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What is the relationship between wavelength and frequency?
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The longer the wavelength the lower the frequency, the shorter the wavelength the higher the frequency
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Electromagnetic spectrum
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Encompasses all forms of electromagnetic radiation
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What is the relationship between energy and frequency in the electromagnetic spectrum?
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As energy increases, frequency increases
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List the types of radiation on the electromagnetic radiation in order of increasing energy
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Radio, microwaves, infrared, visible light, ultraviolet, x-rays, gamma rays
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Quantum
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The minimum amount of energy that can be gained or lost by an atom
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Who discovered the quantum?
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Max Planck (1858-1947)
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What was the prior belief before quantum?
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Energy absorbed/emitted in continuous varying quantities. But Planck discovered that energy increases in infinitesimal steps called quantum.
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Planck's constant
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E quantum = hv
h = 6.626 x 10-34 J x S But "hv" can only be expressed in whole number multiples such as "1v" because energy increases in whole numbers |
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What did Planck conclude?
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Energy of radiation increases as the radiation's frequency increases
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Photoelectric Effect
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Photoelectrons are emitted from a metal's surface when light of a certain frequency shines on the surface
ex: calculators convert light into electrical energy |
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What did Einstein propose in 1905?
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Electromagnetic radiation is wavelike and particlelike
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Photon
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Particle of electromagnetic radiation with no mass, carries a quantum of energy
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What was Einstein's formula for the energy of a photon?
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E photon = hv
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Atomic emission spectrum
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Set of frequencies of the electromagnetic waves emitted by atoms of an element
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Each element's AES is _______.
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Unique, emitts only certain colors/frequenceis
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How did Bohr answer the question: Why do elements' AES allow only certain frequencies of light?
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He proposed a Hydrogen atom has only certain allowable energy states
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Ground State
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Lowest allowable energy state of an atom (to keep it stable)
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What is the relationship between an electron's orbit and an atom's energy state?
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The smaller the electron's orbit, the lower the atom's frequency and vice versa
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How do atoms move from orbit to orbit?
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Like quanta, atoms can move only from 1 allowable orbit to another. Thus, they can emit/absorb only certain amount of energy.
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What did Louis de Broglie predict in 1924?
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If waves have a particlelike nature, do particles have a wavelike nature?
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de Broglie equation
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Predicts that all moving particles have wave characteristics
wavelength = h/mass(v) ex: car wavelengths too small to measure while electrons wavelengths easily measured |
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Heinsberg Uncertainty Principle
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It is fundamentally impossible to know both the velocity and position of a particle at the same time
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Quantum Mechanical Model of Atom
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The atomic model in which electrons are treated as waves
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Who created the Quantum Mechanical Model of the Atom?
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Austrian physicist Erwin Schrodinger in 1926
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What does the Quantum Mechanical Model of the Atom do?
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-Limits electrons to certain values, does not describe electron's path, includes atomic orbital
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Atomic Orbital
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3D region around nucleus that describes the electron's probable location (where most dots are located)
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Principal Quantum Numbers
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Indicate relative sizes and energies of atomic orbitals
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What happens as the principal energy level increases?
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Orbital increases, electron stays farther from nucleus, atom's energy level increases
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Principal Energy Levels
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An atom's major energy levels
ex: n=1 is the ground state - 7 levels - so goes all the way to n=7 |
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Energy Sub levels
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Level 1 has 1 sub level, level 2 has 2 sub levels, and so on
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What are the four sub levels and how many orbitals does each have?
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1. s, 1
2. p, 3 3. d, 5 4. f, 7 |
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Electron Configuration
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Arrangement of electrons in an atom
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What arrangement do electrons tend to assume?
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Ground state electron configuration - the arrangement that gives the atoms the lowest possible energy to keep it as stable as possible
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What three rules define electron arrangement in an atom's orbitals?
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1. aufbau principle
2. pauli exclusion principle 3. hund's rule |
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Aufbau Principle
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Each electron occupies the lowest energy orbital available
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What are the four main features of the aufbau principle?
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1. all orbitals related to an energy sublevel are of equal energy
ex: all 3 2p orbitals have equal E 2. in a multi-electron atom, the energy sublevels within a principal energy level have different energies ex: 2s and 2p diff. energies 3. In order of increasing energy, the sequence of energy sublevels within a principal level is s, p, d, f 4. orbitals related to energy sublevels within one principal level can overlap orbitals related to energy sublevels within another principle level |
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Pauli Exclusion Principle
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A maximum of two electrons may occupy a single atomic orbital, but only if the electrons have opposite spins
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Hund's Rule
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Single electrons with the same spin must occupy each equal-energy orbital before additional electrons with opposite spins can occupy the same orbitals
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How many valence electrons?
S[Ne]3s2sp4 |
6
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