Which element has the highest boiling point at standard pressure 1) mg 2)na 3)rb 4)sr

Sr has highest boiling point at standard pressure

Explanation:

Comparison of boiling points for these given elements require two factors namely- (1) atomic mass and (2) valency

Higher the atomic mass of an element, higher will be its boiling point. Because, with increase in atomic mass, van der waal forces between atoms increase. So more energy is required to boil an element by disrupting this interatomic force.

Higher the valency of an element, higher will be its boiling point. This is due to increase in bonding energy.

Here, Sr has higest atomic mass as well as it is bivalent. So Sr has highest boiling point.

- "the choice that is not an indicator of a chemical change is "state of matter changes". more common than not, chemical reactions produce energy in the form of light or heat. along with energy, they also produce a new substance called the product that could be in any state of matter (solid, gas, or liquid)."