A student’s particulate diagram of an aqueous solution of MgCl₂ shows one Mg²⁺ ion…
CHEMISTRY · Single correct · A Level · Chemistry · Bonding · Bonding
Problem
A student’s particulate diagram of an aqueous solution of MgCl₂ shows one Mg²⁺ ion surrounded by four water molecules with hydrogen atoms pointing toward the Mg²⁺, and two Cl⁻ ions each surrounded by four water molecules with oxygen atoms pointing toward the Cl⁻. Which of the following best identifies an error in the student’s diagram and justifies the correction?
(a) The stoichiometry is incorrect; the diagram should show equal numbers of Mg2+ and Cl− ions to maintain overall charge neutrality.
(b) The orientation around Cl− is incorrect; the oxygen atoms, not hydrogen atoms, should face the Cl− because the oxygen end of water carries a partial positive charge.
(c) The orientation around Mg2+ is incorrect; the oxygen atoms, not hydrogen atoms, should face the Mg2+ because they carry partial negative charge.
(d) The number of water molecules around each ion is incorrect; Mg2+ should attract fewer water molecules than Cl− because its ionic radius is smaller.