Is ammonium chloride dissolving in water in an ice pack exothermic or endothermic?

Consider this initial-rate data at a certain temperature for the reaction described by

As changes in energy levels of electrons increase, the frequencies of atomic line spectra they emit

Click the button that shows the correct relationship of the electron affinities of the elements sodium and phosphorus. sodium’s electron affinity value is more negative than the electron affinity value of phosphorus. phosphorus’ electron affinity value is more negative than the electron affinity value of sodium. this information cannot be determined using the periodic table. answer is b on e2020.