Answer:
gases
Explanation:
because the solid (steel) is the most dense, the gas (air) is the least dense, and the density of the liquid (water) is in between.
Answer:
semipermeability
Explanation:
partially but not freely or wholly permeable specifically : permeable to some usually small molecules but not to other usually larger particles a semipermeable membrane.
If uranium-241 lost 2 protons and 2 neutrons, then thorium-237 would be produced. The number beside the element is the mass number which is the sum of protons and neutrons. If uranium would lose 2 protons and 2 neutrons, then the mass number would decrease by 4 making it 237. Looking in a periodic table, thorium is the element which has a mass number of 237.
Answer:
Explanation:
The Lanthanides were first discovered in 1787 when a unusual black mineral was found in Ytterby, Sweden. This mineral, now known as Gadolinite, was later separated into the various Lanthanide elements. In 1794, Professor Gadolin obtained yttria, an impure form of yttrium oxide, from the mineral.
Alkaline Earth Metals and Alkali Reactive metals because they need more electrons to acquire octet.
