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86 Cards in this Set
- Front
- Back
Mechanical Wave
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A traveling disturbance in material that transports energy that is typically in a repeating shape created when a material vibrates in place. The vibrational energy travels through the material but the material itself stays in the same location.
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Equilibrium Position
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The place where a molecule will reside when no unbalanced forces are acting upon it.
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Compression (Longitudinal) Wave
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A wave in which the molecules of the medium vibrate in the same direction as the wave propagates.
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Shear (Transverse) Wave
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A wave in which the molecules of the medium vibrate at right angles to the direction the wave propagates.
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Surface Waves
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A wave that travels along the surface of a medium.
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Crest
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The part of a wave where the particles are displaced a maximum amount above or in front of their equilibrium position.
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Trough
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The part of a wave where the particles are displaced a maximum amount below or behind their equilibrium position.
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Amplitude
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The maximum amount that a particles will displace from its normal, undisturbed position when a wave passes through it.
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Wavelength
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The distance between successive similar parts in a repeating wave.
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Wave Speed
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The rate that the disturbance travels through a medium and depends on the medium's elastic properties.
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Frequency
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The number of wave amplitude crests that pass a particular point in space every second.
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Hertz
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The unit used to measure frequency, "oscillations per second"
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Reflection
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The act of bouncing off a surface
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Refraction
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The act of changing direction when passing from one medium to another
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Diffraction
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The changing of direction of waves to bend around corners and spread as they encounter obstacles
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Interference
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The canceling and enhancing effect htat occurs when two waves move through the same space at the same time.
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Constructive Interference
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When two or more waves passing through the same space at the same time both disturb the medium in the same way so that the resultant amplitude is larger than the amplitude of each individual wave separately.
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Destructive Interference
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When two or more waves passing through the same space at the same time both disturb the same medium in opposite ways so that the resultant amplitude is smaller than the amplitude of each individual wave separately.
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Standing Wave
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A wave characterized by lack of vibration at certain points, between which areas of maximum vibration occur.
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Node
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A location of no vibration in a standing wave
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Antinode
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A location of maximum vibration in a standing wave
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Doppler Effect
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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.
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Maxwell's Equations
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A set of four fundamental laws, expressed in mathematical form, that govern electricity and magnetism and their interrelationship. The Electrical Force Law is included in Maxwell's Equations.
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Electromagnetic Radiation
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Radiation originating in a varying electromagnetic field, such as visible light, radio waves, x-rays and gamma rays.
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Photoelectric Effect
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The ejection of electrons from metals when light is shined on the metal's surface.
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Photon
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A particle of light. It possesses energy, frequency, and wavelength but neither mass nor charge.
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Planck's Constant
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A value when multiplied by the frequency of light, gives the energy of the photon of light at that frequency.
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Wave-Particle Duality
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The state of possessing both wave and particle properties
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Solid
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A physical state of matter that is characterized by rigidity and resistance to changes in size and shape.
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Liquid
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A physical state of matter that readily changes shape to match its container but that resists changes in volume.
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Gas
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A physical state of matter that readily changes both shape and volume to match its container.
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Plasma
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A physical state of matter characterized by fluid properties in which positive and negative charges move independently.
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Supercritical Fluid
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Materials dissolve more easily in a liquid than in a gas. A supercritical fluid has the property of filling the volume of tis container like a gas, but dissolving materials like a liquid. Both carbon dioxide and water can be put into supercritical states by heating and pressurizing them. Cola and coffee beans are decaffeinated by passing one of these supercritical fluids over them. The caffeine dissolves in the fluid, leaving most of the other chemicals int eh beans behind. Advertisers proclaim the process is "natural" because both carbon dioxide and water occur in nature.
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Compression Force
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A force that is applied in such a way as to compress a material.
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Tension Force
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A force that is applied in such a way as to stretch a material.
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Shear Force
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A force that is applied in such a way as to twist or deform a material.
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Electromagnetic Spectrum
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The entire range of radiation including, in order of decreasing frequency, cosmic-ray photons, gamma rays, x-rays, ultraviolet radiation, visible light, infrared radiation, microwaves, and radio waves.
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Continuous Spectrum
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A spectrum in which the colors blend gradually together without noticeably abrupt changes or missing colors.
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Discrete Spectrum
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A spectrum of separate and distinct colors in which not all colors are present.
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Conductors
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Materials that conduct electricity int eh solid and liquid state.
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Ionic Conductors
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Materials that do not conduct electricity in the solid state, but do when molten or dissolved in water.
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Non-Conductor
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A material which does not conduct electricity in any of its physical states.
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Molecular Model
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The essential defining characteristics of the Molecular Model (also known as the kinetic theory of matter) are: 1) Matter consists of tiny particles called molecules. 2) Each different kind of matter consists of a different kind of molecule. 3) The molecules in matter are in constant motion. 4) Molecules move and interact in accord with laws of motion, the laws of force and the laws of conservation.
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Brownian Model
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The constant, irregular motion of very fine particles (such as fine dust or smoke) suspended in a fluid and observed with a microscope. Brownian motion is taken as evidence for molecules, which collide with the observed particles and cause the jitty motion.
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Atomic Matter
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Matter composed simply of atoms, not molecules.
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Molecules
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The tiny constituent particles of which matter is composed. At this stage in our model, we do not distinguish between atoms and molecules nor do we worry about their sizes or shapes. We only postulate that different kinds of matter consist of different kinds of molecules.
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Thermal Energy (Heat)
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That portion of internal energy that is associated with the kinetic energy of molecules.
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Conduction
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The flow of heat energy from a hot region to a cold region within solid matter.
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Pressure
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Total force divided by the area over which force is applied.
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Alpha Particles
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A positively charged particle that is given off by some radioactive materials including uranium, plutonium, and polonium. Alpha particles are now known to be nuclei of helium atoms.
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Nucleus
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The atomic nucleus is the very dense, positively charged center of the atom.
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Solar System Model
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A model of the atom in which the electrons orbit the small, dense, positively-charged nucleus in elliptical paths. The model was proposed by Rutherford.
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Emission Spectrum
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An emission spectrum is the set of colors of light given off, or emitted, by an object.
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Modified Solar System Model
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The Bohr model with restricted circular orbits of electrons around a dense nucleus.
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Excited States
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Electronic states with quantum number n greater than 1.
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Photon
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A particle of light. It possesses energy, frequency, and wavelength but neither mass nor charge.
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Quantum Mechanics
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The branch of physics used to describe the wave properties of light and matter.
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Probability Curve
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A curve giving the probability of where an object might be detected. The particle is likely to be found where the curve is high and unlikely to be found where the curve is low.
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Probability Wave
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A probability curve that moves in time. At a given moment in time, the places where the wave is high are where the object associated with the wave is most likely to be found.
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Heisenberg Uncertainty Principle
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The product of the uncertainty in an object's position and the uncertainty in its momentum must be greater than or equal to Planck's Constant.
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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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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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Radial Shape
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A cross section of what an orbital would look like if it were sliced in two.
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Shell
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A group of orbitals having similar energies and sizes.
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Spin
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A characteristic of an electron giving the direction of its intrinsic magnetic field.
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Electron Volt
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A small amount of energy used to measure energies of particles in atoms and nuclei. it is equal to 1.6 x 10^-19 joules.
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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 int he same atom can have exactly the same shell, orbital, and spin values.
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Electron State
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The combination of electron shell, orbital, and spin.
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Chemistry
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The discipline in which the interactions of atoms with each other are studied.
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Element
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Matter that contains only one kind of atom.
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Law of Constant Composition
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Substances contain a fixed, definite proportion of elements by mass.
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Atomic Theory
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The model that matter is made up of atoms
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Physical Properties
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Properties like melting or boiling temperature, density, ionization potential
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Chemical Properties
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Properties associated with the chemical reactivity of a material. For example, does a substance combine with oxygen or react with water?
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Periodic Laws
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The properties of the elements are a periodic function of their atomic masses.
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Atomic Number
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The number of protons in a nucleus. This number defines an element.
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Metals
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Elements that are good electrical and thermal conductors and can be hammered into thin sheets or drawn into fine wires.
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Non-Metals
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Elements that do not conduct electricity
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Families or Groups of Elements
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Elements that were grouped together because they had very similar chemical properties and are now known to have the same number of valence electrons. An element family occupies a vertical column in the Periodic Table.
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Periods
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Horizontal rows in the periodic table within which physical and chemical properties change systematically.
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Main Group
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The set of metal and non-metal elements designated with A column headings. They have valence electron configurations involving only s and p electrons.
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Transition Metals
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The set of metal elements designated with B column headings. They have valence electron configurations involving d electrons.
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Atomic Size
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An estimate of the volume occupied by an atom. The number is obtained from the density of the solid state of the element.
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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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Electron Configuration Diagram
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An enumeration of how electrons populate atomic orbitals that is consistent with the "lowest-energy filled first" and "exclusion" principles.
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Valence Electrons
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One or more electrons in the outermost populated electron shell of an atom. Valence electrons determine an element's chemical reactivity.
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