An exothermic process releases heat (warms up), and an endothermic process absorbs heat (cools down). Which solutions are endothermic and which are exothermic? What is the sign of the change in enthalpy, H, in each case? Which solution(s) had little or no change in temperature?
When sodium chloride dissolves in water, the ions dissociate:

periodic trends is an atom that gets larger as the number of electronic shells increase, the radius of atoms increases as you go down a certain group in the periodic table of elements. in general, the size of an atom will decrease as you move from left to right of a certain period.

its first and third is your answer i did the qustion the fourth isnt right

oxygen, selenium, tellurium, and polonium.

they're all from the same group as sulfur (group 16).

yes

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