Unit 4 Vocab And Terms Flashcards
What is amplitude
The height of the wave
The higher the wave…
The greater the intensity
What is wavelength
A measure of the distance between crest to crest or from trough to trough
In what units is wavelength measured
Meters (m)
What is frequency
The number of waves that passes a fixed point per second
What is frequency measured in
Waves/sec (1/s) 1 wave cycle/second= hertz (Hz)
Speed of light
3.00 x 10^8 m/s
Symbol for speed of light
C
Symbol for frequency
V
If wavelength increases then frequency…
Decreases
If wavelength decreases then frequency…
Increases
What is the wavelength of red light waves
700nm
What is the wavelength of violet light waves
400
what is quanta
small amounts of energy that matter can absorb or emit
what is a quantum
the minimum amount of energy that can be gained or lost by an atom
what is the equation to calculate the energy of an electromagnetic wave
e=hv
what is the symbol for Planck’s constant
h 6.626 x 10^-34 Js
what is electromagnetic radiation
energy that travels in the form of waves
what is a photon
a particle of light that carries a quantum of energy
in what units is wavelength usually expressed
meters, centimeters, nanometers
what is a crest
the highest point of a wave
what is a trough
the lowest point of a wave
what could the Bohr model not explain
the emission of different wavelengths of light by heated objects (other than hydrogen)
if energy of a photon increases frequency…
increases
if energy of a photon decreases frequency…
decreases
what are electromagnetic waves
how light travels through space
what are wave properties
- constructively + destructively interfere
- travel at the speed of light
- measurable
- diffract
- refract
what is diffraction
waves spread out as they pass through a tiny opening
what is refraction
separation of light into its individual components caused by the light “bending” due to the light changing speeds as it is possible through the material
particle properties
- photoelectric effect
- have mass
- can have a spin (cw, ccw)
what was the double slit experiment
the double slit experiment by Thomas Young in 1801 was that light & electrons travel like waves through space except when they are being watched. Thomas noticed by observing the behavior, we interfere with the wave pattern and the light/electron starts behaving like a particle. even when firing the electrons one at a time we observe the wave pattern.
what was the photoelectric effect
When a photon hits an electron on the surface of a metal, the electron can be emitted. however, not every electromagnetic wave will cause the photoelectric effect. only electromagnetic radiation waves that carry a minimum amount of energy of higher can cause electrons to be ejected from the surface of the metal.
what is threshold frequency
the minimum frequency needed
what is the atomic emission line spectra
it contains only certain colors or wavelengths of light
what does every element have
its own line spectrum
what did Bohr say about the energy of an electron
that it was quantized
What did Bohr label in the Bohr model of Hydrogen
he labeled each energy level with a quantum number
what is n=1
it is the lowest level of energy
when electrons absorb energy, they jump to an ___ state
excited
what are the excited states of an electron
n=2, n=3, n=4, n=5, n=6, n=7
what happens when an electron falls back from a higher level to a lower level
radiation (light) is emitted
what happens to white light when it passes through a prism
it becomes colored light
true or false: all colors of light travel at the same speed
true
do cool or warm colors have higher energy
cool colors have the highest energy and warm colors have the lowest energy
which color has the longest wavelength
red
what color has the shortest wavelength
violet
what is the relationship between wavelength and the energy of light
the longer the wavelength the lower the energy and vice versa
what color of light has the most energy
violet
what color of light has the least energy
red
which electron transition involves the most energy
from n=1 to n=2
what does Heisenberg’s uncertainty principle state
- the position and momentum of a moving object cannot simultaneously be measured and known exactly
- you cannot predict future locations of particles (electrons)
what did Heisenberg find a problem with
He found a problem with the Bohr model and that there was no way to observe or measure the orbit of an electron
what is the Quantum Mechanical Model
it combines previous ideas and treats the electron like a wave that has quantized energy. it is impossible to state the exact position or momentum of an electron, but you can state a probability of where the electron is located
where the density of an electron cloud is high there is a ___ probability that is where the electron is located
high
if the electron density is ___ then there is a low probability that is where the electron is located
low
what is an orbital
an orbital is a 3D region moving unpredictably where electrons are found in
what is an atomic orbital
a region around the nucleus where an electron with a given energy is likely to be found
where is an electron found 90% of the time
in orbitals
true or false: different sublevels (s, p, d, f) have differently shaped orbitals
true
how many quantum numbers are there
4
the lower the principle quantum number, the ___ the electron is to the nucleus on average
closer
the higher the principle quantum number is, the ___ the electron is from the nucleus on average
farther
what are quantum numbers
Each electron in an atom is described by four different quantum numbers. the first three (n, i, m) specify the particular orbital of interest, and the fourth (ms) specifies the spin of the electron within that orbital.
what is a principle quantum number (n)
the energy level occupied by an electron. it also tell you the relative distance from the nucleus
how many principle quantum numbers are there
infinite
what are the 4 quantum numbers
the principle quantum number, the angular momentum quantum number, the magnetic quantum number, and the spin quantum number
what does n represent in principle quantum numbers
n represents the principle quantum number. n represents the atom’s major energy levels (the number of the electron shell)
what is the angular momentum quantum number (I)
it describes the 3-dimensional shape of the region that an electron is likely to be found. (it also tells you the sublevel)
what is the magnetic quantum number (mi)
It indicates the specific orbital that an electron is likely to found
each sublevel consists of an ___ amount of orbitals
odd
each orbital can hold up to ___ electrons
2
s sublevels have ___ orbital
1
p sublevels have ___ orbitals
3
d sublevels have ___ orbitals
5
f sublevels have ___ orbitals
7
orbitals in higher principle levels get…
larger
what is the spin quantum number (ms)
it indicates the spin direction of an electron in an orbital. the different spin directions are clockwise and counterclockwise
how many electrons can the first energy level hold, what sublevels are available
2 electrons, s
how many electrons can the second energy level hold, what sublevels are available
8 electrons, s and p
how many electrons can the third energy level hold, what sublevels are available
18 electrons, s p and d
how many electrons can the fourth energy level hold, what sublevels are available
32 electrons, s p d and f
what is the electron configuration
1s2 2s2 sp6 3s2 sp6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f14 6d10 7p6
what are the two ways you can write electron configurations
shorthand and longhand
what are orbital diagrams
pictorial descriptions of electrons of electrons in an atom.
what is used to represent the orbitals and electrons
lines and boxes are used to represent the orbitals and arrows are used to represent the electrons
what is the Aufbau principle
electrons always fill the lowest energy sublevel first
what is the Pauli Exclusion principle
each orbital can only hold a maximum of 2 electrons. the electrons must have opposite spins
what is Hund’s rule
electrons will spread out to occupy each individual equal-energy orbital before they begin to pair up
