The nineteenth century held one last great surprise for chemists. It began in 1896 when Henri Becquerel in Paris carelessly left a packet of uranium salts on a wrapped photographic plate in a drawer. When he took theplate out some time later, he was...
For most of us, the periodic table is a thing of beauty in the abstract, but for chemists it established an immediate orderliness and clarity that can hardly be overstated. Without a doubt, the Periodic Table of the Chemical Elements is the most eleg...
The structure of atoms and the significance of protons will come in a following chapter, so for the moment all that is necessary is to appreciate the organizing principle: hydrogen has just one proton, and so it has an atomic number of one and comes...
Mendeleyev used a slightly different approach, placing his elements into groups of seven, but employed fundamentally the same principle. Suddenly the idea seemed brilliant and wondrously perceptive. Because the properties repeated themselves periodic...
Mendeleyev dutifully completed his studies and eventually landed a position at the local university. There he was a competent but not terribly outstanding chemist, known more for his wild hair and beard, which he had trimmed just once a year, than fo...
Despite the occasional tidyings-up, chemistry by the second half of the nineteenth century was in something of a mess, which is why everybody was so pleased by the rise to prominence in 1869 of an odd and crazed-looking professor at the University of...
Because chemists for so long worked in isolation, conventions were slow to emerge. Until well into the second half of the century, the formula H2O2 might mean water to one chemist but hydrogen peroxide to another. C2H4 could signify ethylene or marsh...
No one knew about his principle, because Avogadro himself was a retiring fellow, he worked alone, corresponded very little with fellow scientists, published few papers, and attended no meetings but also it was because there were no meetings to attend...
Fortunately more sober types were at work elsewhere. In 1808, a dour Quaker named John Dalton became the first person to intimate the nature of an atom (progress that will be discussed more completely a little further on), and in 1811 an Italian with...
Soon after taking up his position, Davy began to bang out new elements one after anotherpotassium, sodium,magnesium, calcium, strontium, and aluminum or aluminium, depending on which branch of English you favor. 上任不久，戴维开始宣布发现一...
