Quantum Theory & Atomic Structure Flashcards
A _____ is a discrete, quantized bundle of electromagnetic energy.
PHOTON
Name one use of the Photoelectric effect.
solar panels
garage door sensors
nightlights
The ____ ____ is the region in which there is a high probability of finding an electron.
Electron Cloud
However, the highest probability to find electrons are in their orbitals.
Electromagnetic waves have
A. particle like properties
B. wavelike properties
C. both particle like and wavelike properties
D. neither particle like nor wavelike properties
C. both particle like and wavelike properties
Emission of electrons when electromagnetic radiation falls on an object is
photoelectric effect
What is the Heisenberg Uncertainty Principal state?
The Heisenberg Uncertainty Principal says that it is impossible to measure precisely both the position and momentum of a particle at the same time.
An atom in ____ is an atom with the smallest allowable amount of energy.
a ground state
What does EMR stand for?
Electromagnetic Radiation
What is an EMR consist of?
Consists of oscillating perpendicular electric and magnetic fields moving simultaneously through space as waves.
What are the properties of waves?
Frequency: number of cycles it undergoes per second
Wavelength: the distance the wave travels during one cycle
Speed; distance the wave moves per unit time (for EMR this would be the speed of light “c”)
nm = m? pm = m? A = m?
nm = 10^-9 m pm = 10^-12 m A = 10^-10 m
What is the relationship between wavelength and frequency? and what does this mean for energy?
As wavelength increases, frequency decreases and vice versa. Energy is directly proportional to frequency, so if frequency is decreasing then so is energy.
As wavelength decreases, frequency increases and so does energy.
What are the different EMR’s and which describe wave properties and energy within them?
RMIVUXG
RADIO MICROWAVE IN-FARED VISIBLE LIGHT ULTRA-VIOLET X-RAY GAMMA RAYS
The end near the radio waves has a higher wavelength, lower frequency, and not much energy. Whilst the end near the gamma rays has a lower wavelength, higher frequency, and higher energy.
What is the amplitude and how does it affect brightness?
The amplitude is the height of the waves or troughs from the x axis and represents the intensity or the brightness of the light.
HIGHER AMPLITUDE = MORE INTENSE/BRIGHTER
LOWER AMPLITUDE = LESS INTENSE/DIM
Define “continuum of radiant energy”.
Continuum of kinetic energy describes how each specific type of EMR meets the next. A continuum of the EMR’s as they connect with each other (as displayed in the spectrum).
What part of the electromagnetic spectrum can humans see with their eyes?
The visible nature which ranges from 700nm to 400nm.
Where red is near 700nm and violet is near 400nm.
A way to remember the colours if to use the name of the EMR’S beside visible light.
What is the difference between monochromatic and poly-chromatic light?
Monochromatic light refers to light of a single wavelength whilst poly-chromatic refers to light of many wavelengths.
Is white light poly-chromatic?
Yes, white light is poly-chromatic as it contains many different wavelengths of light.
What is refraction?
When a wave travels at through a different medium at any angle other than 90 degrees. The waves speed changes causing a change in direction called REFRACTION.
What is dispersion and what is it related to?
Dispersion relates to refraction and is defined as to when white light separates (disperses) into its component colours when it passes through a refracting object. This occurs because each wave is refracted at a slightly different angle.
What is diffraction?
Diffraction is when a wave strikes the edge on a object or passes through a slit as wide as it’s wavelength. In doing so, the wave has a tendency to bend around or create semicircular waves on the other side past the object.
What is interference and what is it related to?
Interference is related to diffraction and arises the problem of DOUBLE SLITS. In this situation the nearby emerging waves interact through the process of interference.
CONSTRUCTIVE: the crests and trough match up in phase, and results in an addition of AMPLITUDE
DESTRUCTIVE: the crests meet at troughs and out of phase which results in the subtraction of the AMPLITUDE.
What is a black body?
A black body is an idealized physical body that absorbs all incident electromagnetic radiation, regardless of frequency or angle of incidence. (It does not only absorb radiation, but can also emit radiation)
What is the concept of black body radiation?
Black body radiation tries to create the concept that as a black body solid object is heated it begins to emit visible light. As it is heated to higher temperatures it begins to emit light at different colors because of the changes in wavelength and intensity (this is described as the characteristics of black body radiation).
What is the double slit experiment?
The double-slit experiment in quantum mechanics is an experiment devised by physicist Thomas Young. It shows that light has both a wave nature or characteristic and a particle nature or characteristic, and that these natures are inseparable. … The same is true of electrons and other quantum particles.
How does the black body radiation relate to quantized energy? What did Planck hypothesize?
Max Planck and other scientists developed the quantum theory to explain the black body radiation (to explain the BBR he created the formula E=nh(frequency).
Since black body radiation can only emit certain colors at certain temperatures, Planck hypothesized that the black body could only emit CERTAIN QUANTITIES OF ENERGY. A black body like any other object is made out of atoms, which means that the atoms as they change color –> wavelength –> frequency –> energy are emitting only certain quantities of energy.
THEREFORE, THEY ENERGY OF AN ATOM IS QUANTIZED (occurs in fixed positions).
What is a quantum?
A quantum is a packet of energy.
FORMULA = (frequency)(n)
When energy change occur in an atom?
An atom changes in energy by absorbing or emitting one or more packets of energy (quanta)
What is the smallest allowed energy change in an atom?
Since, atoms emit/absorb energy by quantum packets the smallest allowed change in n=1.
Who came up with the black body radiation?
Max Planck
Who came up with the photoelectric effect?
Albert Einstein
What is the photoelectric effect?
The photoelectric effect is when MONOCHROMATIC LIGHT of a sufficient frequency sines on a metal plate, causing a current to flow.
