What aspect of an element is affected by temperature and pressure?

The physical state of an element is directly affected by temperature and pressure. When temperature increases, for instance, solids can change to liquids (melting), and liquids can change to gases (evaporation). Conversely, lowering the temperature can cause gases to condense into liquids and liquids to solidify. Pressure also plays a significant role; increasing pressure can push gases into a liquid state or even solidify them, depending on the substance. For example, water exists as ice (solid) at low temperatures and under atmospheric pressure, but it can become steam (gas) when heated.

The other aspects listed—atomic mass, nuclear stability, and electron configuration—remain relatively constant under standard temperature and pressure conditions. While kinetic energy and molecular interactions can change, the fundamental properties of an atom, such as its mass and nuclear behavior, are not typically influenced by the environmental conditions of temperature and pressure in everyday situations.