it's an ionic compund, that means it is formed by donating or gaining electrons
Na is writen first than, it must be electropositive i.e it has donated electons which made it positive and the clorine gains electron so it's electronegative.
Na is positive because as we know it's atomic number is 11 that means it has 11 protons and 11 electrons now, when it donate electon it has, greater number of protons whose change is +ve so the atom becomes overall positively charged ion or cation.
and something same happens in clorine and because it gains one electron and the number of electrons increase in it by 1 whise charge is -ve so, the atom becomes negatively charged ion or anion which has a -1 charge.
Evaporation occurs because among the molecules near the surface of the liquid there are always some with enough heat energy to overcome the cohesion of their neighbors and escape. At higher temperatures the number of energetic molecules is greater, and evaporation is more rapid.
Correct answer is magnesium bromide. This is an ionic compound with metal forming a positive ion - K+ and halogen forming a negative ion - Br-. When group 7 element form ions they have a suffix -ide. Bromine is the element and when it forms a negative ion bromine is called bromide with the suffix. Magnesium gives 2 electrons and bromine can take only 1 electron, therefore 2 bromine atoms are needed. Therefore magnesium forms ionic bonds with 2 bromine atoms. The compound is called magnesium bromide