I think the correct answer would be C. The common characteristic that is shareed by the elements found at the center of a period would be that they are the least reactive species. Having lower value of electronegativity, there is less ionization of the atoms which would also contribute to less reactivity.
Answer:
C. 500 cm' of 1.0 mol dmº magnesium sulphate solution.
Explanation:
Let us look at each of the solutions individually;
CaCl2 has three particles
K2SO4 has three particles
MgSO4 has two particles
C2H5OH has only one particle
The number of moles of moles in 250 cm of 2.0 mol dm-3 potassium chloride is 250/1000 * 2 = 0.5 moles having two particles
Also; number of moles in 500 cm' of 1.0 mol dm-3 magnesium sulphate solution= 500/1000 * 1 = 0.5 moles having two particles