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99 Cards in this Set
- Front
- Back
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What is a mechanical wave?
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A disturbance traveling through a medium carrying energy. Energy is transferred by work when mechanical waves move or spread through material.
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What is a Medium?
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Something tangible a mechanical wave travels through. The medium supports the waves motion.
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What is a compression wave?
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A longitudinal wave driven by the force of pressure. Compression waves travel through all states and the bonds are compressed and stretched. A compression wave passing a point causes the molecules at that point to vibrate back and forth in the direction of the waves motion. What are examples? Sound and a vibrating object in contact with air. Also, a person holding hands in a parallel line swaying side to side, moving the other people side-to side. (Slinky).
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What is a transverse or shear wave?
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A wave in which the molecules or the medium vibrate at the right angles to the direction the wave propagates. (Wave moves perpendicular to motion). Shear forces can be exerted on all states of matter. However, the molecule in liquids, gases, and plasmas are not rigidly bound to one another and drift away in the direction the force pushes them. What is an example? A person slamming his fist on a table or football fans doing the “wave” because the people stand up and down while the wave travels at right angles to their motion. The energy decreases as the wave spreads out through the medium.
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What is Wavelength?
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The distance between successive similar parts in a repeating wave. Length between crest to crest.
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What is Amplitude?
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The maximum amount that a particle will displace from its normal, undisturbed position when a wave passes through it. The height of the wave. In other words, amplitude is the distance a particle travels when going from its equilibrium position to a crest or trough. With mechanical waves, greater energy means greater displacement. For sound waves, amplitude Is loudness.
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What is Frequency?
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The number of wave amplitude crests that pass a particular point in space every one second. Frequency relates to color: red is lower, violet is higher. Frequency in audio relates to pitch – higher frequencies produce higher tones. Our ears are sensitive to sound frequencies from 20 to 20,000 hertz.
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What is Wave Speed?
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The rate at which a specific wave disturbance travels from point to point or the rate that a single wave peak travels in a medium. Frequency x wavelength.
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What is Wave Speed dependent on?
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It depends on the medium’s elastic properties, its density, and the type of wave going through it. Speeds vary depending on materials. Frequency ex. Doesn’t increase and remains the same, while the wavelength changes or decreases
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What is Reflection?
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The act of bouncing off a surface. (Sound waves traveling through air reflect when they strike a solid wall). Echoes are another example of reflection.
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What is Refraction?
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The wave changing direction and speed when passing from one medium to another. Bending one material to another. Because of refraction, objects inside denser material appear to be at different positions than they really are. (a stink in water will appear bent). Another example is light exiting a plane glass window. It bends back to its original direction, making objects seen through the window appear normal.
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What is Diffraction?
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? The spreading of a wave around corners or obstacles or through and opening (holes). Diffraction allows sound to be heard around a corner, even when the hearer is not in a direct line with the source. The amount of diffraction depends on the size of the wavelength relative to the size of the opening. If the hole is large compared to the wavelength, little diffraction occurs. We typically don’t notice light diffract because its wavelength is short, but it’s possible. Microwave example – dependence of diffraction on wavelength.
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What is Interference?
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The cancelling and enhancing effect that occurs when two waves move through the same space at the same time. This occurs when two or more waves travel through the same medium at the same time.
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What types of interference are there? |
Constructive interference – When two or more waves passing through the same space at the same time disturb the medium in the same way so that the resultant amplitude is larger than the amplitude of each individual wave separately. (Two rocks dropped in a pond at the same time, near each other). Destructive interference – When two or more waves passing through the same space at the same time both disturb the medium in OPPOSITE ways so that the resultant amplitude is smaller than the amplitude of each individual wave separately. Interference can occur in music with two instruments.
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What is a Standing Wave?
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The result of confined waves interfering in such a way that destructive and constructive interference always occur in a fixed location (LOOKS like it’s not moving). Antinode – maximum motion. Node – no motion. A wave characterized by lack of vibration at certain points. (Shaking a rope up and down).
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What is Doppler Shift?
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A change in the observed frequency of a wave occurring when the source and observer are In motion relative to each other. (The motion of whatever is generating or receiving waves can alter wavelength and frequency). The Doppler shift only measures the relative speed between the sender and the receiver. (Example – boat (different frequencies occur in the water) A police car with a siren passing by – the pitch decreases as it passes).
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What did Galileo determine about the speed of light?
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That it’s extremely fast and its speed was finite. He miscalculated it’s measurement by a lot.
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How did Roemer determine the speed of light? |
Through observing Jupiter’s moons. Every week these moons are eclipsed several dozen times as they orbit behind Jupiter. When Jupiter was farthest from the earth, they came later than they did when Jupiter was nearest.
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How did Fizeau determine the speed of light?
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Sent beam of light through the toothed wheel experiment. Knowing the wheel’s rotation speed, the gap sizes between the teeth, and the distance to the mirror, he was able to calculate speed of light
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In what ways does light behave like a wave?
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? It has wave properties. It diffracts, reflects, refracts, and interferes. Proved through experiments such as the double-slit experiment and using lasers to shoot sheets of model.
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What did Thomas Young demonstrate? |
That light diffracts and interferes like a wave. Created the double slit experiment.
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What medium does light travel through? |
None. Travels through open space and doesn’t need a medium. Light is an electromagnetic wave, not mechanical.
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What is the order of the Electromagnetic Spectrum from least energy to most? |
Radio, microwave, infrared, visible (red, orange, yellow, green, blue, violet) ultra violet, x ray, gamma. Longest wavelength – shortest wavelength. Least energy – most energy.
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What color has the most energy? The least? Which has the longest wavelength?The shortest?
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Violet, Red, Red, violet
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What are some ways light acts like a particle? |
In photography – light hits film and is then treated like a particle. Photo electric effect. Shine light on metal and determined by frequency of light, not the brightness or the amplitude. In Hertz’s experiment, the ejected electrons possessed more energy if the light had a shorter wavelength, like ultraviolet light, than if its wavelength were longer.
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What is Wave-Particle Duality? |
? If diffraction is negligible, electromagnetic waves behave much like particles. If it is prominent, they behave like waves. So in this sense electromagnetic waves have characteristics of both waves and particles at once. Basically, the state of possessing both wave and particle properties.
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Photon |
A particle of light. It possesses energy, frequency, and wavelength but neither mass nor charge. Sharp shadows do not prove that light doesn’t diffract |
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What are the Four States of Matter? |
Solid, liquid, gas, and plasma
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What is a State Change? |
Changes from one state to another. (Ex. Ice melting or water boiling).
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What is Density? |
Mass/volume. Solids tend to be denser than a liquid and liquids are definitely denser than gases. When materials change state, their density changes.
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What is a Compression Force?
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Force that compresses or squeezes a material. |
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What is a Tension Force? |
Force that stretches material
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What is a Shear Force? |
A force that twists or deforms a material. (Works kind of like scissors).
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Which forces do each state of matter support? |
Solids support all three types of forces, Liquids support compression and tension forces, gases support only compression forces, and plasmas aren’t considered here because they contain ionized particles.
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What is a plastic response?
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Doesn’t go back to its shape
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What is an elastic response?
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Bounces back to its shape
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What is a Continuous Spectrum
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The colors blend gradually together without noticeable abrupt changes or missing colors
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What is an Emission Spectrum?
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Mostly dark with a few lines where colors are missing.
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What is an Absorption Spectrum?
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Most of the rainbow with a few lines where colors are missing.
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What is a Conductor?
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allows flow of electricity
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What is a semi-conductor? |
allows flow of electricity when conditions are right
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Ionic conductor |
As solid, electricity doesn’t conduct. It will if it’s melted or dissolved.
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Non - conductor |
Same as insulator. Doesn't permit electrons to flow through it.
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A physical state of matter that readily changes both shape and volume to match its container. |
gas
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Solid |
A state of matter that is characterized by rigidity and resistance to changes in size and shape
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Liquid |
A physical state of matter that readily changes shape to match its container but that resists changes in volume
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plasma |
A physical state of matter characterized by fluid properties but in which positive and negative charge move independently
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What is Brownian Motion? |
The constant, random motion of very fine particles (such as dust or pollen) suspended in a fluid and observed with a microscope.
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What are the Four (or 5) Assumptions of Molecular Model? |
? All matter consists of tiny particles, different kinds of matter are made up of different molecules, the molecules in matter are in constant motion, they obey all of Newton’s laws, and they are indivisible – cannot be broken. Indivisible assumption was wrong because we can form plasma.
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How does the Molecular Model explain different States of Matter and State Changes?
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Solid molecules are locked in place, liquid molecules pass each other with attraction, and gas molecules move completely freely. Plasma doesn’t apply here.
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What is Temperature? |
A measure of the average kinetic energy of the molecules. When gas and liquid molecules are at the same temperature, they have the same average kinetic energy. When matter changes energy, its internal kinetic energy also changes.
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What happens to the Kinetic Energy as Matter heats? |
Kinetic energy states the same. An example would be ice melting. Even though energy is still flowing into the plan, the temperature of the liquid/solid mixture does not increase. Therefore, the kinetic energy is also not increasing, even though the ice is melting.
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What happens to the Electrical Potential Energy during a State Change? I |
increases or decreases
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How does the Molecular Model explain Conduction? |
Molecules increase and wiggle more, which passes energy down. Conduction is the term used when describing heat flowing within solid matter because of a temperature difference.
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How does the Molecular Model explain Gas Pressure?
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Gas inside a container accelerates and hits the wall faster. Heat increases the pressure, as well as more particles increase the pressure. (Example tire pressure on a bicycle).
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- The molecular model’s limitations include the explanation of ....
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color and plasma
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What was the Thomson or “Plum Pudding” Model? Why did he propose this theory?
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Overall atom has positive charge with chunks of negative electrons within (Choc. Chip cookie). Because it explains plasma, which the molecular model couldn’t do.
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What is the Rutherford or “Solar System” model? Why did he propose this theory
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Extremely small, positively charged nucleus with electrons orbiting. Due to the results of the gold foil experiment. One particle reflected – not dense enough to reflect the alpha particle. (Ex. A tank shooting at a tiny piece of tissue paper). Rutherford was NOT expecting it to reflect
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What didn’t the “Solar System” model explain?
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Explained that all matter should glow all the time and that was a problem. Because electrons, like planets, could orbit with any possible acceleration, shouldn’t electrons emit light with a continuous spectrum?
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What is the Bohr of “Modified Solar System Model? What does it explain?
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? Small, dense nucleus with electrons orbiting in a CIRCULAR motion. Electrons are certain distances from the nucleus. What does it explain? Color and light. Gain or lose the right amount of energy. Absorbed – low energy – to high energy. Emitted – high energy – low light.
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What are problems with the Bohr Model?
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Doesn’t say WHY we have special orbits and electrons are still orbiting.
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- In what model do electrons orbit the nucleus so that any orbit allowed by Newtonian physics can be occupied by an electron?
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Rutherford “solar system model”
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What did de Broglie propose about all matter?
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All matter has wave-particle duality
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How does wavelength depend on momentum (mass and velocity)?
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)? As momentum increases, the wavelength becomes smaller. Wavelengths are too small to be meaningful.
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On what size does the wave nature of matter become important?
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Atomic (scale of an atom).
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Do electrons produce Interference Patterns?
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Yes, they behave like waves.
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What is the wave associated with Matter?
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Probability wave
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What is the Heisenberg Uncertainty Principle?
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Limit to amount of information you can have. The more precisely you know the position of an object, the less you will know about its momentum.
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If we know better where a particle is, what information must we lose?
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How it’s traveling or its momentum. The better we know about its position, the less we know about the momentum.
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- To see interference fringes (patterns), the slit's spacing needs to be close in size to the electron's ....
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wavelength
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What is the Quantum Model of Matter?
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The atomic model incorporating the wave aspect of matter.
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How does this agree with the Bohr Model?
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The probability waves describing moving electrons truly do act like waves and can form standing waves.
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What is an orbital?
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A standing wave giving the probability of finding an electron in various locations around the nucleus of an atom.
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What is spectroscopy?
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The study of the brightness and wavelengths of the different frequencies of light emitted by excited atoms and ions.
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What are the different types of orbitals?
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1 wave – first level. First energy level or ground state – electrons will resonate in one pattern called an S orbital (the only orbital with a non-zero probability of the electron being in the nucleus). 2 waves – second level – electrons will resonate in two patterns “s” and “p”. P orbital – an orbital that looks like a dumbbell. D orbital. 3 levels will resonate in “s” “p” and “d” orbitals.
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How many are in each set?
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? P orbitals come in sets of 3. At most, 2 electrons can occupy the same orbital. If two electrons are in the same orbital, the spin must be different. Orbitals S P D F G H I 1 3 5 7 9 11 13 |
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What is the Exclusion Principle
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The rule that two electrons cannot be in exactly the same state in an atom. in other words, no two electrons in the same atom can have exactly the same shell, orbital, and spin values.
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. How many electrons can be in each orbital?
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? In every orbital, you can fit 2 electrons.
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Where do electrons want to be?
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In the lowest energy state
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A group of orbitals having similar energies and sizes
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Shell
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: The shell, orbital, and spin of an electron
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Electron state
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- Which is the only orbital with a non-zero probability of the electron being in the nucleus?
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S
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- The shape of a p-orbital most closely resembles a ...
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peanut or dumbbell
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What is an Element?
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Matter that contains only one kind of atom
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What is the Law of Constant Composition?
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Substances contain a fixed definite proportion of elements by mass. (Certain substances always break down into the same rations of the same materials).
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What is Atomic Theory?
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The model that matter is made up of atoms
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Who created the Periodic Table?
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Dmitri Mendeleev. He began by ordering the elements by atomic weight (mass number).
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What is the Periodic Law?
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The properties of the elements are a periodic function of their atomic masses
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What is Atomic Number?
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? Number of protons (top left corner). The mass is the number of protons and neutrons (bottom left corner).
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How does atomic size change from left to right in a Row?
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gets smaller.
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How does atomic size change from top to bottom in a Column?
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gets bigger
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What is Ionization Energy?
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The amount of energy needed to completely remove an electron from an atom. The energy needed to remove the first electron from a neutral atom varies periodically with atomic number.
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How does it change from left to right in a Row? (ionization energy)
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Gets larger
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How does it change from top to bottom in a Column? (ionization energy)
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gets smaller
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- Different substances can contain the same elements but have different... Such as hydrogen peroxide
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Ratios |
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- The alkali metals have the ______________ ionization energy of the atoms in the row.
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lowest
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- Each metal in Column 1A, the alkali metals, has the _______________ atomic volume.
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Largest
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The two categories of elements are...
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metals and non-metals
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Valence electrons
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One or more electrons In the outermost populated shell of an atom
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