As one proceeds from oxygen to polonium in Group 16 (VIA) of the Periodic Table, the number of valence electrons
for each succeeding element

Well technically there are two correct answers b and d. but for you its probably b in general.good day sir/ma'am : ) (i know not gender)

Ans(15) minutes;

Answer is: value of q is 5·10⁻⁶m.chemical reaction: mg²⁺(aq) + co₃²⁻(aq) → mgco₃(s).c(mg²⁺) = 2.5·10⁻³ m; concentration of magnesium cations.c(co₃²⁻) = 2.00·10⁻³ m; concentration of carbonate anions.q = c(mg²⁺)  · c(co₃²⁻).q = 2.5·10⁻³ m  · 2.00·10⁻³ m.q = 5·10⁻⁶m.q = 0.000005 m.