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Chemistry - The elements

The elements

C, S, Au, Cu, Ag, Fe, Sn, Pb, Hg, Zn, As, Bi, Sb, P, Co, Pt, Ni In the
1600s, Robert Boyle had proposed that a substance should be regarded as an
element until it could be broken down into simpler substances. He
considered elements to be substances that could be identified by
experiment.

N, O, Cl, Mn, Mo, Te, W, U, Zr, H, Ti, Y, Be, Cr. In the late 1700s,
Antoine Lavoisier produced a table of 33 elements. He defined an element as
'the last point which chemical analysis is capable of reaching'.

Nb, Ta, Ce, Pd, Rh, Os, Ir, K, Na, Ba, Ca, Mg, Sr, B, I, Li, Cd, Se, In,
Si, Br, Al, Th, V, La, Tb, Er, Ru. In the early 1800s, Humphrey Davy was
one of the first to use electrochemical cells. He used electrolysis to
extract K, Na, Ca, Ba and Sr from their salts. In 1808, John Dalton
proposed his atomic theory. In 1817, Johann Dobereiner was the first to
make a connection between the chemical properties of elements and their
atomic weights. He discovered that in the set of three elements Ca, Sr and
Ba, not only did Sr have chemical properties similar to Ca and Ba but its
atomic weight was the average of the atomic weights of Ca and Ba.

Cs, Rb, Th, Ga, Ho, Y, Sm, Tm, Sc, Gd, Nd, Pr, Dy, Ge

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