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38 Cards in this Set
- Front
- Back
Allotropes
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two or more forms of the same element that differ in their chemical structure and therefore in their properties
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ozone layer
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refers to the stratospheric region of maximum ozone concentration
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Nucleus
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a minuscule and highly dense region composed of protons and neutrons
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Protons
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positively charged particles
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Neutrons
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electrically neutral particles
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Electron
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Much smaller mass than a proton or neutron and a negative electric charge equal in magnitude to that of a proton
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periodic properties
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array of elements that vary in a regular way with increasing atomic number and that repeat at regular intervals
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Outer (valence) electrons
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found in the highest energy level and help to account for many of the observed trends in chemical properties
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isotopes
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two or more forms of the same element (same number of protons) whoes atoms differ in number of neutrons, and in mass
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mass number
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the sum of the number of protons and neutrons in the nucleus of an atom
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covalent bond
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two electrons that are shared
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Lewis structure
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a representation of an atom or molecule that shows its outer electrons
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single covalent bond
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only one pair of shared electrons form the linkage between atoms
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structural formula
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a representation that replaces each bonded electron pair in a lewis structure with a line
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octet rule
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the fact that electrons in many molecules are arranged so that every atom (except hydrogen) shares in eight electrons
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Polyatomic molecules
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Consist of three or more atoms
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double bond
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a covalent bond consisting of two pairs of a shared electrons
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triple Bond
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a covalent linkage made up of three pairs of shared electrons
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resonace forms
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lewis structures that represent hypothetical extremes of electron arrangements in a molecule
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wavelength
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the distance between successive peaks
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freguency
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the number of waves passing a fixed point in 1 second
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nanometer (nm)
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one-billionth of a meter (m)
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electromagnetic spectrum
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ranges from short and high-energy X-rays and gamma rays to long and low-energy radio waves
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radiant energy
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is used to refer to the entire collection of different wavelengths, each with its own energy
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ultrociolet (UV)region
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Lies at wavelengths shorter than those of the visible color of violet
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infrared (IR)
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at wavelengths longer than those of red visible light, one encounters
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quantized
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the energy distribution is not really continuous, but consists of many individual steps
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photons
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individual bundles of energy
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steady state
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a condition in which a dynamic system is in balance so that there is no net change in concentration of the major species involved
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Chapman cycle
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the set of natural steady-state reactions for stratospheric ozone
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free radical
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a highly reative chemical species with one or more unpaired electrons
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chlorofluorocarbons (CFCs)
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compouns composed of the elements chlorine, fluorine, and carbon
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Halons
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compounds similar to CFCs, in which bromine or fluorine atoms replace some or all of the chlorine atoms
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catalyst
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a chemical substance that participates in a chemical reaction and influences its speed without undergoing permanent change
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polar stratospheric clouds (PSCs)
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water vapor present freezes into ice crystals, forming thin stratospheric clouds
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effective stratospheric chlorine
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reflecting both chlorine and bromine-containing gases in the stratosphere
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hydrochlorofluorocarbons (HCFCs)
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compounds of hydrogen, chlorine, fluorine and carbon
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hydrofluorocarbons (HFCs)
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compounds of hydrogen fluorine, and carbon
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