Hi there! quick question: why are some elements more reactive to other elements?

valence electrons.

sodium only has one valence electron on its outer shell so it is very easy for it get rid of it and a lot of other elements wanna mess with it. but something like argon has full valence shell so it does not do anything with its electrons since its alreadt full. the atoms want to get a full shell, so sodium wants to lose it asap

definition

                    entropy is a measure of the randomness or the extent of disorder of a chemical process.

                      enthalpy is a measure of the heat change of a reaction occurring at a constant pressure.

measurement units:

                        entropy is measured in joule per kelvin (jk⁻¹)   whereas enthalpy is measured in joule per mole (jmol⁻¹)

requirements:

                            entropy has no requirements or limits, and its change is measured by the division between the heat change of the chemical process and the temperature.

                              in contrast, enthalpy can only be related to the heat change of the reaction under standard conditions.

o conteúdo de calor de um sistema é igual à entalpia apenas para um sistema que é constante