Chemistry - an illustrated guide to science (794128), страница 34
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This list is restricted tothe 89 naturally occurring elements.Table of naturallyoccurring isotopes 6Table of masses and abundance of naturally occurring isotopesAtomicnumber(Z)ElementSymbolMassnumber(A)Percentage72HafniumHf174176177178179180180181180182183184186185187*184186187188189190*192*191193190192194195196198197196198199200201202204203205206*207*208*210*0.25.218.627.113.735.20.0199.990.226.414.430.628.437.162.90.021.61.613.316.173TantalumTa74TungstenW75RheniumRe76OsmiumOsSymbol● “Symbol” refersto the shorthand formof the element’s name used inchemical equations.Mass number● Them ass n u m ber (A) represents thenumber of protons or neutrons in thenucleus of one atom of that element.Not all atoms of the same elementhave the same mass number.
Atoms ofan element that have different massnumbers are called isotopes.77IridiumIr78PlatinumPtPercentage● “Percentage” refersto isotopicabundance. For example, 99.99percent of naturally-occurringhydrogen has the mass number 1.Only 0.01 percent has the massnumber 2.7980GoldMercuryAuHg81ThalliumTlAtomic massm ass” refers to the averageatomic mass of that element's isotopeweighted by isotopic abundance.© Diagram Visual Information Ltd.● “Atom ic* denotes radioactive isotope38.561.50.832.97.21000.110.016.923.113.229.86.929.570.5————Atomicmass175.9403176.9419177.9425178.9444179.9451179.9457180.9462179.9450181.9465182.9485183.9491185.951184.950186.9550185.9529186.9550187.9550188.9572189.9574191.9605190.9599192.9623189.9592191.9605193.9624194.9645195.9646197.9675196.96655195.96582197.96677198.96826199.96834200.97031201.97063203.97348202.97233204.97446205.97608206.97745207.98201209.99000197Table of naturallyoccurring isotopes 7RADIOACTIVITYKey wordsTable of masses and abundance of naturally occurring isotopesAtomic Elementnumber(Z)828384LeadBismuthPoloniumSymbolPbBiPo85AstatineAt86EmanationEm8788FranciumRadiumFrRa89ActiniumAc91ProtactiniumPa92UraniumUMassnumber(A)Percentage204206207208210*211*212*214*209210*211*212*214*210*211*212*214*215*216*218*215*218*219*220*222*223*223*224*226*228*227*228*230*231*232*234*231*234*234*235*238*1.425.221.751.7————100—————————————————————————100———0.0060.71899.276atomic massatomic numberisotopemass numberAtomicmassAtomic number203.97307205.97446206.97590207.97664209.98418210.98880211.99190213.99976208.98042209.98411210.98729211.99127213.99863209.98287210.98665211.98886213.99519214.99947216.00192218.0089214.99866218.00855219.00952220.01140222.0175223.01980223.01857224.02022226.0254228.03123227.02781228.03117230.0331231.03635232.03821234.0436231.03594234.0434234.04090235.04393238.0508● Theatom ic n u m ber (Z) of an elementis the number of protons in thenucleus of one atom of that element.All atoms of the same element havethe same atomic number.Element● “Element” refersto the common nameof the element.
This list is restricted tothe 89 naturally occurring elements.Symbol● “Symbol” refersto the shorthand formof the element’s name used inchemical equations.Mass number● Them ass n u m ber (A) represents thenumber of protons or neutrons in thenucleus of one atom of that element.Not all atoms of the same elementhave the same mass number. Atoms ofan element that have different massnumbers are called isotopes.Percentage● “Percentage” refersto isotopicabundance.
For example, 99.99percent of naturally-occurringhydrogen has the mass number 1.Only 0.01 percent has the massnumber 2.Atomic mass● “Atom icm ass” refers to the averageatomic mass of that element's isotopeweighted by isotopic abundance.© Diagram Visual Information Ltd.* denotes radioactive isotope198KEY WORDSKey wordsaccelerator A chemical that increases the rate of a chemicalreaction.acid Any substance that releases hydrogen ions when addedto water.
It has a pH of less than 7.© Diagram Visual Information Ltd.acid-base indicator A chemical compound that changescolor when going from acidic to basic solutions. An exampleis Methyl orange.acidity The level of hydrogen ion concentration in asolution.actinides The name of the radioactive group of elementswith atomic numbers from 89 (actinium) to 103(lawrencium).actinium (Ac) A silvery radioactive metallic element thatoccurs naturally in pitchblende and can be synthesized bybombarding radium with neutrons.actinium series One of the naturally occurring radioactiveseries.activation energy The energy barrier to be overcome inorder for a reaction to occur.active site The part of an enzyme where the chemicalreaction occurs.addition polymerization A chemical reaction in whichsimple molecules are added to each other to form long-chainmolecules without by-products.addition reaction A reaction in which a molecule of asubstance reacts with another molecule to form a singlecompound.adsorption The process by which molecules of gases orliquids become attached to the surface of another substance.aerosol Extremely small liquid or solid particles suspendedin air or another gas.alcohol A member of a family of organic compounds whosestructure contains the –OH functional group.aldehyde One of a group of organic compounds containingthe aldehyde group ( –CHO).
Names have the suffix -al.aldohexose A monosaccharide having six carbon atoms andan aldehyde group.aldose A sugar containing one aldehyde group per moleculealkali A solution of a substance in water that has a pH ofmore than 7 and has an excess of hydroxide ions in thesolution.alkali metals Metallic elements found in group 1 of theperiodic table. They are very reactive, electropositive, andreact with water to form alkaline solutions.alkaline earth metals Metallic elements found in group 2of the periodic table.alkalinity Having a pH greater than 7.alkane A member of the hydrocarbon group whose generalformula is CnH2n+2. They have single bonds between thecarbon atoms and are not very reactive.alkanol See alcoholalkene A member of the hydrocarbon group whose generalformula is CnH2n. They have a double bond between a pair ofcarbon atoms and are thus reactive.alkyl A member of the hydrocarbon group whose generalformula is CnH2n+1.alkyne A member of the hydrocarbon group with thegeneral formula CnH2n–1.
They have a triple bond betweena pair of carbon atoms in each molecule and are thusreactive.allotrope An element that can exist in more than onephysical form while in the same state.alloy A metallic material made of two or more metals or of ametal and non-metal.alpha decay The process of radioactive decay in which thenucleus of an atom emits an alpha particle.alpha particle A particle released during radioactive decaythat consists of two neutrons and two protons.aluminum (Al) A silvery-white. metallic element that isnon-magnetic and oxidizes easily.amine A member of a group of organic compoundscontaining the amino functional group –NH2.amino acid An organic compound containing both thecarboxyl group (–COOH) and the amino group (–NH2) .ammonia (NH3) A colorless, strong-smelling poisonous gasthat is very soluble in water.ammonium hydroxide (NH4 OH) An aqueous solutionof ammonia.
It is a corrosive chemical with a strong odor.ammonium ion (NH4 + ) An ion found in ammoniasolution and in ammonium compounds.amphoteric Exhibiting properties of both an acid and a base.anhydride The substance remaining when one or moremolecules of water have been removed from an acid or abase.anhydrous Containing no water. Term applied to saltswithout water of crystallization.anion An ion having a negative charge.anode The electrode carrying the positive charge in asolution undergoing electrolysis.anomer A stereoisometric form of a sugar, involvingdifferent arrangements of atoms or molecules around acentral atom,aqueous solution A solution in which water is the solvent.argon Ar.
A colorless, odorless. gaseous element. One of thenoble gases.aryl A member of an aromatic hydrocarbon group formed bythe removal of a hydrogen atom from an aromatichydrocarbon.association The process by which molecules of a substancecombine to form a larger structure.astatine At. A non-metallic radioactive element that is highlyunstable and rare in nature.atmosphere The layer of gases surrounding Earth.atom The smallest particle of an element that can exhibitthat element’s properties.atomic emission spectrum The amount ofelectromagnetic radiation an element emits when excited.atomic mass The ratio of the mass of an average atom ofan element to 1/12th of the mass of an atom of the carbon-12isotope.atomic number The number of protons in the nucleus ofan atom.atomic volume The volume of one mole of the atoms ofan element.Avogadro’s constant The number of particles present ina mole of substance.199azeotropic mixture A mixture of liquids that boils withouta change in composition.bakelite A phenol/methanal resin that has good electricaland heat insulation properties.base A substance existing as molecules or ions that can takeup hydrogen ions.beta decay The process of radioactive decay in which thenucleus of an atom emits a beta particle.beta particle A high-speed electron emitted by the nucleusof certain radioactive elements during beta decay.Big Bang The primeval explosion that most astronomersthink gave rise to the Universe.black hole An object with infinite density.body-centered cubic packing A crystalline structure inwhich one atom sits in the center of each cube.boiling point The point at which a substance changes fromthe liquid state to the gas state.bond The chemical connection between atoms within amolecule.
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