Ionic Bonding

magnesium has 12 protons; it loses 2 electrons to achieve a full outer shell, leaving 10 electrons; 12 protons and 10 electrons gives a net charge of 2+

metals lose electrons to form positive ions; non-metals gain electrons to form negative ions

2−

Fe²⁺; Fe³⁺

SO₄²⁻

AlCl₃

Ca(NO₃)₂

(NH₄)₂CO₃

magnesium forms a 2+ ion and chlorine forms a 1− ion; two Cl⁻ ions are needed to balance the 2+ charge on one Mg²⁺ ion

calcium transfers 2 electrons; each chlorine atom can only accept 1 electron, so two chlorine atoms are needed to accept both electrons

magnesium atom has 2 outer electrons shown as dots; both electrons are transferred to the oxygen atom; oxygen gains 2 electrons and has 8 outer electrons, forming Mg²⁺ and O²⁻

the strong electrostatic attraction; between oppositely charged ions

each Na⁺ ion attracts multiple Cl⁻ ions and vice versa; the attractions extend in all directions forming a giant ionic lattice, not discrete molecules

sodium chloride has a giant ionic lattice; there are many strong electrostatic attractions between Na⁺ and Cl⁻ ions; a large amount of energy is required to overcome these attractions

Mg²⁺ and O²⁻ have greater charges than Na⁺ and Cl⁻; so the electrostatic attractions between ions are stronger and more energy is required to overcome them

the ions are held in fixed positions in the lattice; they cannot move to carry charge

the ionic lattice is broken apart and the ions become free to move; the mobile ions carry charge through the solution

solid potassium bromide does not conduct electricity because the ions are in fixed positions; molten potassium bromide does conduct electricity because the ions are free to move; in both cases the charge carriers are ions, not electrons