Final answer:
The statement is false; ionic crystals form when ions pack together to optimize attractive forces, not to achieve a net zero force. Ionic crystals exhibit characteristics like high melting points and brittleness due to the strong attractions between oppositely charged ions.
Step-by-step explanation:
The statement that an ionic crystal results from packing the constituent ions such that there is net zero force of attraction and repulsion is false. Ions in an ionic crystal are arranged in such a way that the attractive forces between oppositely charged ions are optimized. These ionic bonds occur due to the electrical attraction between cations (positively charged ions) and anions (negatively charged ions). The packing results in an alternating pattern of positive and negative ions. To maintain stability, the ions adjust to minimize the repulsive forces between like charges and maximize the attractive forces between opposite charges.
In the case of sodium chloride (NaCl), the crystal lattice is formed by alternating Na+ cations and Cl- anions in a tightly bound three-dimensional structure, which is the characteristic of an ionic compound. This results in a crystalline substance that exhibits high melting and boiling points, and brittleness due to the strong interionic attractions. However, the idea of zero net force would suggest a balance between attraction and repulsion that is incorrect, as the net force is actually an overall attraction that holds the ionic crystal together.