Contributors in Science
Science > General science 
praseodymium
Science; General science
A chemical element, Pr, atomic number 59, and atomic weight 140.91. Praseodymium is a metallic element of the rare-earth group. The stable isotope 140.907 makes up 100% of the ...
platinum
Science; General science
A chemical element, Pt, atomic number 78, and atomic weight 195.09. Platinum is a soft, ductile, white noble metal. The platinum-group metals—platinum, palladium, iridium, ...
radium
Science; General science
A chemical element, Ra, with atomic number 88. The atomic weight of the most abundant naturally occurring isotope is 226. Radium is a rare radioactive element found in uranium ...
rhenium
Science; General science
A chemical element, Re, with atomic number 75 and atomic weight 186.2. Rhenium is a transition element. It is a dense metal (21.04) with the very high melting point of 3440°C ...
sulfur
Science; General science
A chemical element, S, atomic number 16, and atomic weight 32.064. The atomic weight reflects the fact that sulfur is composed of the isotopes 32 S (95.1%), 33 S (0.74%), 34 S ...
strontium
Science; General science
A chemical element, Sr, atomic number 38, and atomic weight 87.62. Strontium is the least abundant of the alkaline-earth metals. The crust of the Earth is 0.042% strontium, making ...
silver
Science; General science
A chemical element, symbol Ag, atomic number 47, atomic mass 107.868. It is a gray-white, lustrous metal. Chemically it is one of the heavy metals and one of the noble metals; ...
Sub-categories
- Acoustics (1199)
- Basic science (4082)
- General science (120567)