The forces holding together an ionic solid are much stronger than the forces between particles in a molecular solid. How are these strong forces reflected in the properties of an ionic solid?
a) strong hydrogen bonding exists between discrete molecules
b) strong dipole-dipole forces exist between oppositely charged ions
c) strong hydrogen bonding exists between atoms
d) strong electrostatic forces exist between discrete molecules
e) strong electrostatic forces exist between oppositely charged ions
I chose B because it makes the most sense. Ionic solids are not made of discrete molecules, molecular solids are. It was a toss up between B and E, but I'm not sure what "electrostatic" forces are and if they're different than dipole-dipole.
Thanks!
I think E is the correct answer. The answer in B refers to dipole-dipole forces BETWEEN OPPOSITELY CHARGED IONS. Oppositely charged ions do attract each other but those are ionic forces and not dipoles. There are ion-dipole bonds, too, especially in solution form, but again thos are ion-dipole and n ot dipole-dipole forces.
In a crystal solid, the positive ions and negative ions are held together in a crystal lattice by the electrostatic attraction from the oppositely charged ions. In NaCl, for example, the Na^+ attract the Cl^- in an alternating structure of the two ions in the crystal lattice. Electrostatic forces are just the attraction for ions to each other as opposed to dipole-dipole, ion-dipole, London, and other types of forces between molecules and clusters of molecules.
I think I understand, but the thing that I'm still a bit confused about is how ionic forces and dipoles differ. If dipole-dipole is + to -, then are ionic forces opposite charges as well? They must be in order to attract.
Sorry if I'm being stupid.
strong electrostatic forces exist between oppositely charged ions
Because the answer says ions
You made a logical choice, and your reasoning is correct. The correct answer is indeed option (e) - strong electrostatic forces exist between oppositely charged ions.
Ionic solids are composed of a three-dimensional array of closely packed positive and negative ions. The forces holding these ions together in an ionic solid are called electrostatic forces. These forces result from the attraction between positively charged ions (cations) and negatively charged ions (anions).
These electrostatic forces are significantly stronger than the forces between particles in a molecular solid, which tend to be weaker and more temporary. In molecular solids, the forces between discrete molecules are typically dipole-dipole forces or London dispersion forces, which are relatively weak compared to the strong electrostatic forces in ionic solids.
Dipole-dipole forces refer to forces between polar molecules that have partially positive and partially negative ends. These forces arise due to the attraction of opposite charges. On the other hand, electrostatic forces in ionic solids involve the attraction of full positive and negative charges between ions.
So, in summary, the strong electrostatic forces between oppositely charged ions in an ionic solid are reflected in its properties, such as high melting points, brittleness, and conductivity when molten or in solution.