First, let's balance the equation.
Sodium chloride can be written as NaCl, sodium element is Na and chorine is Cl
Because the ratio of sodium and chlorine on both sides is 1:1, the equation is balanced as it is and can be written as NaCl⇄Na +Cl
Now, to determine if ΔS is positive or negative.
S refers to the entropy, or the energy, in a reaction. If the entropy in a reaction increases, ΔS is positive. The opposite is also true. To figure out the change in entropy, determine if a reaction has a different amount of molecules than it initially began with. Changes in states of water (solid to gas, gas to liquid, etc.) also allow you to determine if entropy increased or decreased.
In this reaction, NaCl (solid) dissociated to Na (aqueous) and Cl(aqueous). As aqueous is a type of liquid state, entropy is increasing, meaning ΔS is positive.
To figure out if a process in endothermic or exothermic, understand that this is refereing to the heat either absorbed or released during the process. Usually when ΔH is positive/ greater than 0, as given in the problem, it will always be endothermic.