In the nucleus. The nucleus is where the protons and the neutrons of the atoms are. Electrons are only have around 1/2000 of a proton's mass, so it is usually ignored
In 1803AD, Osmium was discovered by Smithson Tennant when dissolving an impure sample of platinum in aqua regia, a mixture of hydrochloric and nitric acids. He was able to determine that the black powder left behind after dissolving the platinum was actually a mixture of two new elements, indium and osmium.
•Osmium is a bluish-white and shiny metal.
•Osmium is very hard and is brittle even at very high temperatures.
•Osmium has the lowast vapor pressure and the highest melting point among the platinum group of metals.
•Osmium's density is slightly more than iridium hence is credited as the heaviest element.
Physical Properties: Sodium bicarbonate is an odorless, white crystalline solid or fine powder. It has a slightly alkaline taste. Its density is 2.20 g mL-1 and it decomposes in temperatures above 50 ºC. The decomposition yields to sodium carbonate. It is highly soluble in water and poorly soluble in acetone and methanol. It is insoluble in ethanol.
Chemical Properties: Sodium bicarbonate is an amphoteric compounds, it means the compound has a character acids an basic at the same time. It is highly soluble in water, resulting in a slighty alkaline solution.
i hope this part helps i will continue to research on Toothpaste's properties
I would say C is the most correct.
In D it depends on what water source you're using. Let's say it is a waterfall, then the source of the water (melting ice or a lake) may disappear in the future.
If you're using underwater "windmills" placed in the ocean, then you would expect it to last a while as the ocean will not disappear in the near future.
