Mendeleev used known relative atomic masses to create the periodic Table TanhUa II. nr Nas sawn. Mewtrahesa sin ecrecreeaaye screwy Iweecwnn aaeweren. Ilepenesarssa (en steinem Hn,不 yPus Pressre工8O6aeT”,y,cpa(187r Tpes ryans Tpy rp PUns PBn L H=1 Tunevecsie arestLi-7=% B=ll C=l2N=140==t9 11Pa1Na=23Mr=24Al=27as=28P=31s=32c=15 2..K=2Ca=40=44T1=30Y=51Cr-52Mm=55Fc=56,C-59 N=1.Cu=63 3..(Ca=6Z=55 a7: As7s Seis Bral 4.1.b=ssr=s7Y=6=90Nh=94Ma=%-100|g=104.Bh=104 5.Ag=10响Cd=12t=13s=118sb=122Te=12J=127 6,Cs=138a=127 =137C=1382 Ta=182w=18 Os=199°.Ir=1 9.Aa=19)Hg=20T=204P=207B=206 =19 吧P6 10画 Th=232 Ur=240 试M(a以n0Ra HO R Rro RrO Weare sampo:see sIN RO MAN ROT (RH RH. RHA RH RHMendeleev used known relative atomic masses to create the Periodic Table In 1860s, many scientists found that the properties of elements tended to recur in cycles, exhibiting the periodicity. In 1869, Dmitri Mendeleev produced a chart summarizing the properties of known elements. Main disadvantage of Mendeleev’s chart: ordered according to atomic masses. Today’s periodic table was ordered according to atomic numbers (原 子序数)