Chapter 4 - Arrangement of Electrons in Atoms Flashcards
How are atoms and light related?
When matter (made of atoms) is energized, it gives off light
What is electromagnetic radiation?
A form of energy that exhibits wavelike behavior as it travels through space
What is the order of the electromagnetic spectrum?
Radio-Microwave-Infrared-Visible-Ultraviolet-X-ray-Gamma
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What is wavelength and what is its symbol?
The distance between corresponding points on adjacent waves (lambda l with extra spoke on the left)
What is frequency and what is its symbol?
The number of waves that pass a given point is a specific time, usually one second (v)
What is the equation between wavelength and frequency and how are wavelength and frequency related?
c = lambdav (the speed of light (3.0010^8 meters/second) equals wavelength (meters) times frequency (per second). Therefore, wavelength and frequency are inversely related.
What is the experiment that proved the wave theory of light, who did it and what pattern was produced?
The double slit experiment by Young which showed an interference pattern (only produced from waves, not particles)
What is the photoelectric effect and what does it prove?
The emission of electrons from a negatively charged metal when certain frequencies of light are shone on it, light also has properties of particles (electron radiation is absorbed only in numbers of photons (E=hv) and if a photon’s frequency is below the minimum, electrons remain bound, different metals bind their electrons more or less tightly)
What is a quantum, what is the name for a quantum of energy (+amount of mass) and what does that mean?
A quantum is the minimum amount in which something can be found, for light it is called the photon (no mass). A quantum of energy is the quantity of energy that can be lost or gained by an atom
What is the equation for the the relationship between a quantum of energy and the frequency of radiation, who discovered it, and how are frequency and energy related?
E = hv (the energy in a photon (joules) is equal to Planck’s constant (6.62610^-34 joulessecond) times the frequency (per second). Max Planck. Higher frequency means higher energy.
What does the “dual wave-particle” nature of light mean?
Light behaves both as a particle and a wave
What was the problem with the Rutherford model?
It did not explain how the negatively charged electrons are arranged with respect to the positive nucleus. They should attract and the electron would lose energy and spiral into the nucleus.
How did the Bohr model improve upon the Rutherford model?
It used fixed orbits in which the electrons would not use energy. It also said that the energy of the electron is higher when it is farther from the nucleus.
What is emission?
When an electron falls to a lower energy level a photon is emitted (E3 -> E1)
What is absorption?
When an electron jumps to a higher energy level when energy is added (E1 -> E2)
What is the name for the lowest energy state of an atom?
Ground state
What is the name for the state of an atom in which it has higher potential energy than in its lowest state?
Excited state
What is a line-emission spectrum, and what is the importance of hydrogen’s?
A diagram or graph that indicates the degree to which a substance emits radiant energy with respect to wavelength, when electric current was passed through a vacuum tube containing hydrogen gas at low pressure a pinkish glow that could be separated into four colors. Bohr explained it as the the energy differences between the atom’s energy states were fixed
Who discovered that electrons could be considered waves?
Louis de Broglie
What is diffraction?
The bending of a wave as it passes by the edge of an object or through a small opening (like a double slit)
When does interference occur?
When waves overlap
What is the Heisenberg uncertainty principle?
Since any attempt to locate a specific electron will knock it off course, it is impossible to know both the position and velocity of an electron or any other particle
Who discovered an equation that treated electrons as waves?
Schrodinger
What is quantum theory?
A mathematical description of the wave properties of electrons and other very small particles
What are the regions that electrons exist in? (not Bohr)
Orbitals, 3-d regions around the nucleus that indicate the probable location of an electron
What is the purpose of quantum numbers and what are they?
To describe the properties of atomic orbitals and the properties of electrons in orbitals. Principal (n, main energy level, positive integers, total orbitals in a shell = n^2), Angular momentum (L, shape of orbital, number of shapes = n, L = 0 to a max or (n-1)) Magnetic (m, orientation from -L to +L) and Spin (+- 1/2 which means clockwise or counterclockwise)
What is electron configuration?
The arrangement of electrons in an atom
What is the ground state configuration of an element?
The lowest-energy arrangement of the electrons
What is the Aufbau principle?
An electron occupies the lowest energy orbital that can receive it
What is the Pauli exclusion principle?
No two electrons can have the same set of four quantum numbers
What is Hund’s rule?
Orbitals of equal energy (for instance the three orbitals of p) are each occupied by one electron before any orbital is occupied by a second electron, and all electrons in singly occupied orbitals must have the same spin state
What is orbital notation?
An unoccupied orbital is represented by a line, with the orbital’s name written underneath the line, the lines are labeled with the principal quantum number and sublevel letter
What is electron-configuration notation?
The number of electrons in a sublevel is shown by adding a superscript to the sublevel designation, Ex: Helium is 1s^2
What is noble-gas notation?
the most recent noble gas in brackets, then continue with the electron-configeration
What is the highest-occupied energy level in an atom?
The electron-containing main energy with the highest principal quantum number
