How do elements behave under pressure?

For elements without orbital transfer at high pressure, electronegativity first increases and then decreases, while chemical hardness monotonically decreases as pressure increases. For some active metals, the chemical hardness has a further increase at pressures of the order of tens-hundreds of gigapascals.

Explanation:

c, liquids evaporate, creating a gas

it should have an internal chamber and two thermometers sticking out of the top. the internal chamber will also be closed off from the outside.