Unit 5 test Flashcards
What are electrons?
subatomic particles with a negative charge
Where are electrons?
In shells or energy levels that surround the nucleus of an atom
What did Bohr’s model show?
Negative electrons circle the positive nucleus at fixed distances called energy levels
What was Schrodinger’s theory?
Electrons travel in waves. Bohr’s model was wrong because he restricted the electrons to specific orbits.
What are orbitals?
Regions around the nucleus where electrons are most likely to be. These were identified by Schrodinger.
What kind of shapes did Schrodinger believe the orbitals were?
Spheres, peanuts, double peanuts, or flowers.
What is the quantum mechanical model?
Modern model that is also commonly called the electron cloud model. Each orbital around the nucleus resembles a fuzzy cloud. The darkest, densest areas of the cloud are where the electrons have the greatest chance of being.
What are energy levels?
fixed distances from the nucleus where electrons may be found.
True or false: as you go farther from the nucleus, electrons at higher levels have more energy.
trueeeeeeeeeeeeeeee
What are valence electrons?
electrons in the outermost energy level. They determine properties of the atom like how reactive they are.
what are principle energy levels and how are they like a parking garage?
on each level are “parking spots” for electrons. The orbitals are areas within a principle energy level that contain the parking spots, and each spot has a unique number.
What are the four orbital (sublevel) types?
s, p, d, f
how many electrons do each of the orbitals shapes hold?
s holds 2, p holds 6,, d holds 10, and f holds 14
What is the electron configuration of lithium (3)?
1s^2 2s^1
What is the Aufbau principle?
Each electron occupies the lowest energy orbital available.
What is the Pauli exclusion principle?
A maximum of 2 electrons can occupy a single orbital, but only if they have opposite spins.
What is Hund’s rule?
single electrons with the same spin must occupy each equal energy orbital before additional electrons can occupy the same energy level orbitals.
True or false: valence electrons can be transferred or shared in a reaction
TRUEEEEEEEEE
What is the Octet rule?
Atoms are most stable when they have 8 electrons in their outer (valence) shell. every atom tries to attain this arrangement. Atoms tend to gain, lose, or share electrons until they have 8 valence electrons
Why do noble gasses have no desire to react with other elements?
They have a full outer shell of 8 valence electrons
what is an electromagnetic wave?
waves that consist of vibrating electric and magnetic fields.
define electromagnetic radiation.
The transfer of energy by electromagnetic waves
How does an electromagnetic wave begin?
an electrically charged particle vibrates, causing a vibrating electric field, which in turn creates a vibrating magnetic field. The two vibrating fields form together into an electromagnetic wave.
What happens when electromagnetic waves strike matter?
they may be reflected, refracted, defracted, or absorbed.
What are some sources of electromagnetic waves on Earth?
The sun, as well as em waves that depend on technology like radio waves, microwaves, and x-rays
How is the energy of an electromagnetic wave related to its frequency?
Higher frequency waves have more energy
How can we calculate frequency and wavelength?
Speed of light = wavelength times frequency. wavelength = speed of light divided by frequency
What is the order of the electromagnetic structure, from longest wavelengths to shortest?
radio waves, microwaves, infrared, visible light, ultraviolet, x-rays, gamma rays
how can you remember the order of the EMS (electromagnetic spectrum)?
Raging Martians invade Venus using x-ray guns
What are radio waves?
EM waves with the longest wavelengths, lowest frequency, and least amount of energy.
What are microwaves?
EM waves with long wavelengths and low frequencies. They are used for microwave ovens, cell phones, and radar.
What is the difference between AM radio and FM radio?
AM radio encodes sound by changing either the amplitude for AM radio or the frequency for FM radio
How does a cell phone use microwaves to encode and transmit sounds?
A cell phone encodes the sounds of the caller’s voice in microwaves by changing the frequency of the waves. The encoded microwaves then travel through the air to a cell tower and eventually to the receiver of the person being called.
What does radar stand for?
radio detection and ranging
Relate sunlight to the electromagnetic spectrum. Where do the waves that are commonly called light fall on the spectrum?
sunlight contains the complete range of wavelengths of electromagnetic waves.
light includes infrared light, visible light, and ultra violet light
Define infrared light.
light with the longest wavelengths and lowest frequencies
how can infrared light be detected?
you can’t see it, but you can feel it as heat.
What is visible light?
A very narrow range of wavelengths that falls between infrared light and ultraviolet light. it is the only light people can see.
What determines the color of visible light?
Different wavelengths of visible light appear as different colors.
Describe ultraviolet light.
shorter wavelengths and higher frequencies than visible light
How and why should you protect your skin from ultraviolet light?
While it’s energy can be useful for killing germs, too much exposure to ultraviolet light can damage skin.
What are x-rays?
high frequency waves with more energy than any waves other than gamma waves
How are x-rays used?
they are used to make images of bones and teeth inside the body and to see inside luggage at airports.
Why are x-rays dangerous?
they can penetrate the body, damage cells and cause cancer.
What are gamma rays?
shortest wavelengths and highest frequencies. more energy than any other em waves
What are some sources of Gamma rays?
radioactive atoms, nuclear explosions, and stars
how can gamma rays be used to treat cancer?
They can destroy cells, produce mutations, and cause cancer, but can also be used to cure cancer by focusing the deadly rays on cancer cells.
What is a transverse wave?
A wave in which particles of the medium vibrate perpendicular to the direction that the wave travels
define wave amplitude
the maximum distance the particles of the medium move from their resting positions when a passes through
how does the energy of a disturbance affect the wave amplitude?
a wave caused by a disturbance with more energy has a greater amplitude
what is wavelength
a way of measuring waves, usually measured in meters
What is wave frequency?
wave frequency is the number of waves that pass a fixed point in a given amount of time.
what is the SI unit for wave frequency?
hertz. 1 hertz equals 1 wave passing a fixed point in one second
relate wave frequency to the energy of waves
a higher frequency waves has more energy than a lower frequency waves of the same amplitude
what is ground state configuration?
the most stable state where all electrons are in the lowest energy levels available.
what happens when atoms in ground state are heated to a high temperature?
some electrons absorb the heat energy, allowing them to jump to a higher energy level. This is called the excited state. This is unstable, so the electrons fall back to their normal positions.
What happens when excited electrons return to their normal levels?
The absorbed energy is emitted as electromagnetic energy. Some of this may be inn the form of visible light
What is the absorbtion spectrum?
light emitted by atoms consists of specific wavelengths, and each wavelength corresponds to a specific color
true or false: the emission spectrum is unique for each spectrum
TRUEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE
what are photons?
A quantum of light. Tiny, particle like bundles of radiation absorbed and released by electrons. Energy increases with wave frequency.
How can spectroscopy help us analyze and identify an energy source?
emission is different for every element
What are some types of spectroscopy?
atomic absorbtion, atomic emission, ultraviolet, visible, x-ray, infrared
What is the purpose of the flame test?
to observe the characterstic colors produced by certain metallic ions when vaporized in a flame and then to identify and unknown metallic ions by means of its flame test
What are three problems with the flame test
we see colors differently, mixing of the elements, things catching on fire.
What is a quantum??
the smallest discrete unit of a phenomenon
