填空题
An earth scientist has rejigged (调整) the periodic table (元素周期表) to make chemistry simpler to teach to students.
1 But Bruce Railsback from the University of Georgia says he is the first to create a table that breaks with tradition and shows the ions (离子) of each element rather than just the elements themselves.
"I got tired of breaking my arms trying to explain the periodic table to earth students," he says, criss-crossing (交叉) his hands in the air and pointing to different hits of a traditional table. 2 But he has added contour lines to charge density, helping to explain which ions react with which.
"Geochemists just want an intuitive sense of what"s going on with the elements," says Albert Galy from the University of Cambridge. 3
4 He explains that sulphur (硫), for example, shows up in three different spots—one for sulphide (硫化物), which is found in minerals, one for sulphite (亚硫酸盐), and one for sulphate, which is found in sea salt.
He has also included symbols to show which ions are nutrients, and which are common in soil or water. 5
A. And the size of element"s symbol reflects how much of it is found in the Earth"s crust.
B. The traditional periodic table was well drawn.
C. Railsback has listed some elements more than once.
D. "I imagine that this would be good for undergraduates."
E. There have been many attempts to redesign the periodic table since Dmitri Mendeleev made it up in 1871.
F. Railsback has still ordered the elements according to the number of protons they have.