英语课前演讲 一则重要新闻ppt课件

Apieceofnews.,byXiaolin,1,2,Fourchemicalelements（113，115，117，118）havebeenformallyaddedtotheperiodictable（周期表）,completingthescheme（图表）sseventhrow.Theyarethefirsttobeincludedinthetablesince2011,whenelements114and116wereadded.Thefirsttrueiteration（重复）ofthetablewasproducedin1869bytheRussianchemistDmitriMendeleev.Thenewadditionswereformallyverified（核实）bytheInternationalUnionofPureandAppliedChemistry(IUPAC)on30December2015.ThebodyannouncedthatateamofRussianandAmericanresearchershadprovidedsufficient（充足的）evidencetoclaimthediscoveryofelements115,117and118.,3,Howdoelementsgettheirnames?,IUPACawardedcreditforthediscoveryofelement113toaJapaneseteamattheRikenInstitute.Newelementscanbenamedafteramythological（神话的）concept,amineral（矿物）,aplaceorcountry,aproperty（性质）orascientist.AftertheresponsibleIUPACdivision（部门）acceptsthenewnamesandtwo-lettersymbols,theywillbepresentedforpublicreviewforfivemonths.Soelement113maybenamed,4,113JaJapanium,5,Elementsnamedafteraplaceoracountry,Continents：95Am:americium(镅)-America63Eu:europium(铕)-EuropeCountries:87Fr:francium(钫)-France32Ge:germanium(锗)-GermanyStates:98Cf:californium(锎)-California,6,Elementsnamedafterascientist,96Cm:Curium(锔)-Curie99Es:Einsteinium(锿)-Einstein101Md:Mendelevium(钔)-Mendeleev102No:Nobelium(锘)-Nobel104Rf:Rutherfordium(钅卢)-Rutherfurelium107Rh:Bohrium(钅波)-Bohr,7,Whydoweh