Problem: A historian discovers a nineteenth-century notebook in which some observations, dated 1822, were recorded on a substance thought to be a new element. Here are some of the data recorded in the notebook: "Ductile, silver-white, metallic looking. Softer than lead. Unaffected by water. Stable in air. Melting point: 153 oC. Density: 7.3 g/cm3. Electrical conductivity: 20% that of copper. Hardness: About 1% as hard as iron. When 4.20 g of the unknown is heated in an excess of oxygen, 5.08 g of a white solid is formed. The solid could be sublimed by heating to over 800 oC." Judging from the figure, might this nineteenth-century investigator have been the first to discover a new element?

FREE Expert Solution

We’re being asked to determine if the recorded substance is a new element judging from this figure


We will first determine the element based on the description and determine if a new element was discovered.


The description of the substance is 

  • Physical: ductile, silver-white, metallic looking, softer than lead
  • Solubility: unaffected by water, stable in air
  • Melting point: 153 °C
  • Density: 7.3 g/cm3
  • Electrical conductivity: 20% that of copper
  • Hardness: About 1% as hard as iron
  • Derivatization: when 4.20 g of the unknown is heated in an excess of oxygen, 5.08 g of a white solid is formed.
  • Sublimation point: 800°C   
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Problem Details

A historian discovers a nineteenth-century notebook in which some observations, dated 1822, were recorded on a substance thought to be a new element. Here are some of the data recorded in the notebook: "Ductile, silver-white, metallic looking. Softer than lead. Unaffected by water. Stable in air. Melting point: 153 oC. Density: 7.3 g/cm3. Electrical conductivity: 20% that of copper. Hardness: About 1% as hard as iron. When 4.20 g of the unknown is heated in an excess of oxygen, 5.08 g of a white solid is formed. The solid could be sublimed by heating to over 800 oC." A periodic table is shown with the elements colored by era of discovery. An accessible periodic table can be found here: https://media.pearsoncmg.com/bc/bc_0media_chem/periodictable/table.html.  In Ancient times 9 elements were discovered: C, S, Fe, Cu, Ag, Sn, Au, Hg, and Pb.  In the Middle Ages to 1700 6 elements were discovered: P, Zn, As, Sb, Pt, and Bi.  From 1735 to 1843 42 elements were discovered: H, Li, Be, B, N, O, F, Na, Mg, Al, Si, Cl, K, Ca, Ti, V, Cr, Mn, Co, Ni, Se, Br, Sr, Y, Zr, Nb, Mo, Rh, Pd, Cd, Te, I, Ba, Ce, Tb, Er, Ta, W, Os, Ir, Th, U.  From 1843 to 1186 He, Sc, Ga, Ge, Rb, Ru, In, Cs, La, Pr, Nd, Sm, Gd, Dy, Ho, Tm, Yb, Tl were discovered.  From 1894 to 1918 Ne, Ar, Kr, Xe, Eu, Lu, Po, Rn, Ra, Ac, Pa were discovered. From 1923 to 1961 Tc, Pm, Hf, Re, At, Fr, Np, Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No, Lr were discovered.  And from 1965 to the present Rf, Db, Sg, Bh, Hs, Mt, Ds, Rg, Cn, Uut, Fl, Uup, Lv, Uus, Uuo were discovered.

Judging from the figure, might this nineteenth-century investigator have been the first to discover a new element?

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