Chemistry 4.1 and 4.2 Quiz
photoelectric effect
Emission of electrons from a metal when light shines on the metal; Must have minimum frequency and energy for the electrons to be ejected
quanta
Energy exists as particles called _______________.
decreases
As wavelength increases, frequency ____________________.
principal quantum number followed by the letter of the sublevel
"Each atomic orbital is designated by the _____________________________________________" Example: In the 3s sublevel = 3s orbital in the 3rd main energy level Example: In the 3p sublevel = 3px orbital, 3py orbital, and 3pz orbital in the 3rd main energy level
magnetic quantum number (m)
"indicates the orientation of an orbital around the nucleus"
angular momentum quantum number (l)
"indicates the shape of the orbital"
diffraction
"refers to the bending of a wave as it passes by the edge of an object or through a small opening"
principal quantum number (n)
"symbolized by n, indicates the main energy level occupied by the electron" n can be positive integers n=1, 2, 3, etc. The greater the value of n, the greater the energy of the electron and the farther it is from the nucleus
interference
"the combining by superposition of two or more waves that meet at one point in space"
spin quantum number
"two possible values - (+1/2, -1/2)-which indicate the two fundamental spin states of an electron in an orbital"
Rutherford
-Gold foil experiment found that there was a dense center called the nucleus -Incomplete because still don't know where the negatively electrons are
-s orbital (l=0)
-One possible orientation around the nucleus (Davis et al. 108) -One possible m value, m = 0
electromagnetic radiation
-a form of energy that exhibits wavelike behavior as it travels through space. (energy that the electron possesses) -X-rays, ultraviolet (sunburn), visible light (rainbow) infrared light/ radiant (heat to toast your bread), microwave radiation (to heat food), and radio waves/TV
frequency
-is defined as the number of waves that pass a given point in a specific time, usually in one second. -Measures how often wave rises and falls
Schrödinger
1926 _________________________ developed an equation that treated electrons in atoms as waves
p orbital (l = 1)
3 possible orientations around the nucleus py px pz -3 possible m values, m= -1, 0, +1
d orbital (l = 2)
5 possible orientations around the nucleus 5 possible m values, m=-2, -1, 0, +1, +2
f orbital (l = 3)
7 possible orientations about the nucleus 7 possible m values
shell
A main energy level is sometimes referred to as a "______________________."
energy
As a charged particle moves it will give off _____________, therefore light, as it radiates
higher energy level
When matter absorbs energy, the electrons become excited and move to a ___________________________________________________.
increases
As frequency decreases, wavelength __________________.
electromagnetic spectrum (Only a ___________ portion of electromagnetic spectrum is visible from 400 nm to 700 nm which is visible to the human eye.)
All forms of electromagnetic radiation from this wide range of wavelengths and frequencies
absorbing; releasing
Electrons can move from a lower energy level to a higher energy level by _________________________ energy and from a higher energy level to a lower energy level by __________________ energy.
hydrogen
Bohr came up with the model of the _____________________ atom.
energy levels
Bohr had the idea that electrons exist in certain _________________________, overcoming attraction.
higher
Bohr had the idea that the _______________ energy levels were farther from the nucleus. Energy is added to get farther out.
lower
Bohr had the idea that the __________________ energy levels were closer to the nucleus.
nucleus
Electrons are always moving around the nucleus and so possess potential and kinetic energy. But they can only possess certain values of energy, or have specific energy levels. According to Bohr's model of the atom, electrons orbit about the ___________________ much like the way planets orbit the sun. Different energy levels are associated with the different orbits.
electrons
Diffraction experiments also showed that beams of ______________________ show interference.
energy
Each color of the line emission spectrum represents a different amount of ________________, hence a different energy level that the electron was moving from.
s- spherical p-peanut d-daisy f-flower
Each l value has a letter associated with it, in which the letters indicate the shape: list them.
photons; energy
Each time an atom falls to a lower state (excited to ground), _________________ are emitted and ________________ is released.
Schödinger Wave Equation
Electrons are also in quantized energy levels
Bohr Model
Electrons are in quantized orbits
orbitals
Heisenberg uncertainty principle and Schrödinger's equation determined that wave functions give only the probability of finding an electron at a given place around the nucleus. Electrons don't travel around the nucleus in neat orbits as Bohr thought but exist in certain regions called __________________________.
The frequency of the light emitted is observed in line-emission spectrum of an element (which can be measured) in the equation E=hv.
How can the energy levels of the atom be determined by measuring the light emitted from an atom?
2, as long as they have opposite spins
How many electrons can be in one atomic orbital?
8
How many electrons can occupy the second main energy level?
4
How many orbitals are in the 2nd main energy level?
5
How many orbitals are present in the d sublevel?
1
How many sublevels exist in the first main energy level?
distinct lines
Hydrogen gas in a discharge tube was investigated. Light from this type of discharge tube created a pink glow. When passed through a prism, this results: hydrogen emission spectrum in the visible region. Classical theory predicted that hydrogen atoms would be excited by whatever amount of energy was added to them. They expected a continuous spectrum (like a rainbow) (Davis et al. 100) Instead, they saw __________________ __________________.
s
If the principal energy level is 1, what are the shape of the sublevels?
s, p
If the principal energy level is 2, what are the shape of the sublevels?
s, p, d
If the principal energy level is 3, what are the shape of the sublevels?
s, p, d, f
If the principal energy level is 4, what are the shape of the sublevels?
light
Imagine a mouse running through a dark house. If you hear the mouse you can have an idea where its at. When you shine the flashlight on the mouse however it will turn and run at a different direction than it would have gone without the light. Similar to light with an electron. Light's effect on the electron makes it impossible to know the electron's exact location and velocity at the same time. (remember ______________ will excite electrons so that's why they move)
Louis de Broglie
In 1924, he asked the question, "can electrons 'have a dual wave-particle nature as well'" Electrons in Bohr's quantized orbits seemed to have wave properties.
visible light
In the excited state, the atom soon emits the same amount of energy absorbed then oes back to stable ground state. This energy is seen as _____________________________________.
unstable
In the excited state, the atoms absorbs energy. Energy is gained to move farther out. The excited state is _____________________.
For an electron to be emitted from metal, the electron has to be hit by a photon with at least minimum energy.
In what was does the photoelectric effect support the particle theory of light?
dual wave nature
Light has a _______________________ and can act as both a wave and a particle.
photons
Light may behave as a stream of particles called quanta or ______________________. Each particle carries a quantum of energy These particles are called _________________.
frequencies
Louis de Broglie proposed: "electrons can be considered [as] waves confined to a space around an atomic nucleus" These waves have certain ______________________ which therefore have certain energies (E=hν) Just like orbits have certain energies (Davis et al. 104)
quantum; E=hv
Max Planck suggested that light has a particle nature. He called the minimum quantity of energy that can be lost or gained by an atom a ______________________ of energy. The relationship between a quantum of energy and its frequency is expressed in the equation __________________.
2
Maximum of _________ electrons per orbital with opposite spins
photons
Modern theory says that light is BOTH a wave and particle. The particles are called ______________.
px, py, pz
Name the 3 kinds of p orbitals.
energy levels; orbits
Niels Bohr proposed that the atom contains __________________- where the electron is located. He called these energy levels _____________.
2n^2
Number of electrons in a main energy level=
n^2
Number of orbitals in a main energy level=
shapes
Number of possible orbital _______________ = n (Davis et al. 107) n = 1, 1 possible shape n = 2, 2 possible shapes . . . . Etc.
three dimensional
Orbitals orient themselves in _____________________ space
energy levels
When metal salts are exposed to a flame, they produce a unique color because of the electrons falling to lower ____________________.
types of quantum numbers
Principal Quantum Number Angular Momentum Quantum Number Magnetic Quantum Number Spin Quantum Number
n, n, n^2, 2n^2
Principal energy level = Number of sublevels per energy level = Number of orbitals per energy level = Number of electrons per energy level =
probability
Schrödinger determined that wave functions can only give the ______________________ of finding an electron at a given place around the nucleus. ----Propeller of an airplane -You can see each part of the propeller when its at rest (no kinetic energy) -As the propeller moves it takes a different shape - that of a disk- and its position at any one instant is less certain. -Electrons are much smaller than propellers and move more quickly creating even greater uncertainty -Thought of as a cloud (electron clouds) -Different regions in space or orbital's are created!
wave
Scientists knew that "any __________________ confined to a space can only have certain frequencies"
wave...particle
Scientists knew that light could behave as both a _____________________ and a ____________________. Could electrons, which are particles, have wave-like behavior?
fundamentally incorrect
The Bohr Model of the Atom was later proved _____________________________________.
photon
The Line Spectrum Proved: When an excited H atom fell from excited state to its ground state, it emits a ______________ of radiation. Energy given off is the same as what it absorbed. Energy is directly proportional to frequency and inversely proportional to wavelength (the higher the drop the more energy) (that's why each has its own color!)
photoelectric effect;frequency
The ____________________________ is the emission of electrons from a metal when light shines on the metal. In order for this effect to occur, the light must have a minimum _____________________ to eject the electron.
energy
The _______________________________ level of an electron is not the only information determined from the Schrödinger wave equation
greater
The smaller the wavelength, the __________________ the energy.
light
The current heats atoms up causing an increase in energy. Electrons become excited and move to a higher energy level. When they come back down they produce ______________! Infrared →2,200°C = visible light!
frequency; lines
The energy that is released is related to a specific _______________________. These specific frequencies are observed as ___________________ on the line-emission spectrum of hydrogen.
line-emission spectrum
The four bands of light that was separated into four specific colors of the visible spectrum that resulted when a narrow beam of the emitted light was shined through the prism
Ground state is the lowest; excited is the higher state of energy
What's the difference between the ground state and excited state of an electron?
releasing/decreasing in
These electrons eventually fall back down to a lower energy level by ____________________ energy. This energy can sometimes be seen as visible light.
line-emission spectrum; difference
This model helped to explain the ___________________________________________________________________ of the hydrogen atom. Each line of the spectrum was the result of the energy released by the atom when an electron fell to a lower energy level. The energy released is equal to the ________________________ between the higher energy level and the lower energy level.
orbital
When an excited H atom fell from excited state to its ground state, it emits a photon of radiation. Only absorbed what it needed to move up to a specific ___________________ (minimum energy was met). Electrons move around the nucleus only at distances that correspond to those amounts of energy.
gas
When energy is passed through a ________ at low pressure, different colors can result: This is how neon signs work!
energy
When frequency increases/decreases, so does ______________________.
continuous spectrum
When light is passed through a prism, the light separates into its various wavelengths. When white light is passed through, the rainbow appears. This is an example of a ___________________________.
When an atom moves from excited state to a lower energy state (ground state)
Under what circumstances can an atom emit a photon?
flame test
Unknown elements can be identified by using a __________________________ and observing the color produced. The same idea explains how fireworks produce light.
inverse relationship
Wavelength and frequency have an _________________________ so when one goes up the other goes down! If you decrease the wavelength you will get more waves
energy
What does E symbolize?
speed of light
What does c symbolize?
Planck's constant
What does h symbolize?
frequency
What does v symbolize?
wavelength
What does λ symbolize?
number of orbitals in a main energy level
What is represented by the formula, n^2?
c= λv
What is the equation that shows the relationship among the speed of light, frequency, and wavelength?
E=hv
What is the equation that shows the relationship between the energy of a quantum of light and the frequency of a quantum?
E=ch/ λ
What is the equation that shows the relationship between the energy of a wave and its wavelength?
9.7 x 10^14 Hz
What is the frequency of light that has a wavelength of 310 nm?
6.626 x 10^-34 j·s
What is the numerical value of Planck's constant?
3.00 x 10^8 m/s
What is the speed of light?
9.4 x 10^9 m
What is the wavelength of electromagnetic radiation if its frequency is 3.2 x 10^-2 Hz?
peanut
What shape is represented by the letter p?
daisy
What shape would an orbital in the 3rd sublevel have?
s only
What sublevels are possible for the first main energy level?
1p
Which is not a possible combination? 2s 3p 3d 1p
Electrons have to drop to lower energy levels to produce ultraviolet than infared.
Why does electromagnetic radiation in the ultraviolet region represent a larger energy transition than does radiation in the infared region?
magnetic field
You can think of the electron as spinning similar to the Earth on its axis. Spin states create a _____________________________________. There are two possible spin states for an electron.
angular momentum quantum number (l)
___ can have different values They "are zero and all positive integers less than or equal to n - 1" (Davis et al. 108) = 0, . . . , n-1 For example, in principle energy level 1 (n = 1), ________ is 0. In principle energy level 2 (n=2), _____ is equal to 0 and 1. (remember, l = 0, . . . , n-1
Bohr
______________ deduced that: -electrons inside an atom possess different energies -electrons in the first orbit belong to the first energy level -electrons in the second orbit belong to the second energy level -electrons in the third orbit belong to the third energy level...... etc -each energy level of an atom could only accommodate a certain number of electrons.
Quantum
_______________________ numbers can be used to describe the properties of orbitals and the properties of electrons in the orbitals
Heisenberg
________________________ in 1927 proposed an idea that involved detection of electrons by their interactions with photons -Photons and electrons have about the same energy -locating an electron with a photon will knock it off its course -there is always an uncertainty with the location of an electron
quantum theory (Schrödinger)
describes mathematically the wave properties of electrons and other very small particles
wavelength
distance between corresponding points on adjacent waves (measures crest to crest)
ground state
electron in lowest energy level possible (stable)
energy (in joules)=Planck's constant x frequency (e=hv)
formula for energy
energy (in joules)=speed of light x Planck's constant/wavelength(E=ch/λ)
formula for energy
frequency=speed of light/wavelength (v=c/λ)
formula for frequency
speed of light=wavelength x frequency
formula for speed of light
wavelength=speed of light x frequency (λ=cv)
formula for wavelength
wavelength=speed of light x Planck's constant/energy (λ=ch/E)
formula for wavelength (when energy is given)
Heisenberg uncertainty principle
impossible to determine simultaneously both the position and velocity of an electron or any other particle
energy levels
regions of space in which electrons can move about the nucleus of an atom
magnetic quantum number
symbolized by m; Values of m can be -l to +l
orbital
three-dimensional region around the nucleus that indicates the probable location of an electron