Mendeleev used known relative atomic masses to create the periodic table AnnuA II. n, Typus Pressre X06aB°,且cpa8ir Tpyass Tpys Tpyans Press Tpyuns Ryans Tpyaas Ipyons vIll, sepesoIk . yl.Yll H=1 Tanavecsi aarwraTu Li-7. B=ll== F=t9 Pa1LNa=2=24A1=272a8=28P=31s=32c 2.L.K=2Ca=40=4T=0V=51Cr=52Mm=5Fe=56,Ca-59 3..(C a7:As75 SisEr 100Ru=104.Bh=1 Pd=104,Ag=108 5.Ar=106Cd=12tn=135s=118sb=122Te=12J=127 中F ..Cs=13Ba=137|-=137C=13 Ta=182w=18 0s=19°.=19s 9.k.Aa=19n)Hg=200T=204P=2071B=20形 Th=232 Ur=240 B以Ma时叫0RB2O2 1O R,o, R10 RO Bucare -ope:so aw RO MA RO R RH. RH: 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)