Which of the following usually have lower melting points than ionic solids a) atomic solids b) molecular solids c) network solids d) metallic solids

The correct answer is option b, that is, molecular solids.

Explanation:

Generally, the ionic compounds exhibit much higher melting points in comparison to molecular compounds. The ionic compounds are held together by ionic attractions between the negative and positive ions. These are known as ionic bonds. In order to melt or break an ionic component, there is a need to disrupt these bonds. This needs an ample amount of energy.  

The molecules are held in the association through covalent bonds, these are robust, and however, there is no requirement to dissociate these covalent bonds in order to melt a molecular component. Each and every molecule is neutral in molecular solids and is fascinated by its adjacent neutral molecule with the help of an intermolecular force.  

Thus, to melt a molecular component, one requires to dissociate these weak intermolecular forces between the neutral molecules. That is why ionic compounds usually exhibit higher melting points in comparison to the molecular compounds.  

answers: to make sure that all of the broken pieces of tablet were added to the water, to allow for fair comparison of all three trials, with different particle sizes to avoid experimental error

there is none because earth is stationary and flat.