Properties of matter can be broadly classified into two categories:
-Physical properties, these usually involve a change in the state of matter
-Chemical properties. these involve a change in the chemical composition of matter.
Now, physical properties can be further classified as:
Extensive: these depend on the amount of the substance, eg: mass, volume
Intensive: these do not depend on the amount of the substance eg: density, color, melting point, boiling point
A physical property that does not describe a change in state is color. For example: copper sulfate is a compound which is a blue in color. Thus, color provides information which describes the appearance of matter. In contrast, properties like melting or boiling point suggests a change in the state of the substance.
Because the attractive forces are governed by the relationship

we know that the bond strength between the ions of opposite charge depends on the charges on the ions and the distance between the centers of the ions when they pack to form a crystal.
In the example of MgO (magnesium oxide) and NaCl, MgO has a much higher lattice energy because the ions are +2 and -2, instead of +1 and -1.
But your problem doesn't deal with the magnitude of the charge; it concerns the ionic radii.
Smaller ions are packed closer together, meaning the attractive forces are working across a smaller distance and are thus stronger. We know based on periodic trends that as you move down a group, the ion radius increases. Therefore, the lattice energy decreases.
Both Mg and Ca are alkaline earth metals (group II on the periodic table). But Mg is one row above Ca, meaning its ionic radius is smaller. Therefore, its lattice energy is larger.
Answer:
60.66 %
Explanation:
The mass percentage of chlorine is 60.66 % chlorine in the compound sodium chloride. To calculate this, add together the mass of one mole of sodium
Neon is a noble gas which means it has 8 valence electrons. An electron becomes stable and inert when it has 8 valence electrons.
Fluorine has 7 electrons and needs 1 more to become stable. This makes Fluorine highly reactive compared to Neon, which is already stable.