Ionic Bonding
5 marks · EasyThis question is about the formation of ions and charges in ionic bonding, including magnesium oxide and another compound.
State the charge formed on a magnesium ion in magnesium oxide.
Magnesium is in Group 2 of the Periodic Table. Explain why the charge on a magnesium ion is the value you stated in part (a).
State the charge formed on the oxide ion in magnesium oxide.
When potassium forms an ionic compound with chlorine, what is the formula of the ion formed by potassium? Include its charge.
Explain, in terms of electrons, how a chlorine atom forms an ion.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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(a) 2+
(b) Magnesium loses 2 electrons as it has 2 electrons in its outer shell (Group 2), forming a 2+ ion.
(c) 2-
(d) K+
(e) Chlorine gains 1 electron to form a chloride ion with a 1- charge.
Show mark scheme and worked solution
Marking points
A1 (a) · 1 mark · Correct charge for magnesium ion (2+).
B1 (b) · 1 mark · Explanation that magnesium loses 2 electrons (Group 2) to form a 2+ ion.
A2 (c) · 1 mark · Correct charge for oxide ion (2-).
A3 (d) · 1 mark · Correct formula and charge of potassium ion (K+).
B2 (e) · 1 mark · States that chlorine gains 1 electron, forming a Cl- ion.
Worked solution
a) The charge on a magnesium ion in magnesium oxide is 2+.
b) Magnesium is in Group 2, so it has 2 electrons in its outer shell. It loses these two electrons to achieve a noble gas electronic structure, forming an ion with a 2+ charge.
c) The charge on the oxide ion in magnesium oxide is 2-.
d) Potassium forms a K+ ion when it reacts with chlorine.
e) A chlorine atom gains 1 electron to form a chloride ion (Cl-) with a 1- charge.