Recommend an element use to fill bottles that contain ancient paper. the element should be a gas at room temperature, should be denser than helium, and should not easily react with other elements.

Okay so we are given these requirements:

element which can be used to stuff bottles that enclose ancient paper
must be a gas at room temperature
must be denser than helium
must not react with other elements

The only element that comes into my mind is:

Argon

to make a supersaturated solution, make a saturated solution of sugar by adding 360 grams of sugar to 100 ml of water at 80 degrees celsius. when the water cools back down to 25 degrees, that 360 grams of sugar will still be dissolved even though the water should only dissolve 210 grams of sugar.

atomic number of carbon is 6

electronic configuration of carbon is 1s²2s²2p²

orbital diagram of c is as shown here in the image.