The question requires us to explain the differences in radii of neutral atoms, cations and anions.
To answer this question, we need to keep in mind that a neutral atom presents the same number of protons (positive particles) and electrons (negative particles). Another important information is that the protons are located in the nucleus of the atom, while the electrons are around the nucleus. Also, there is an electrostatic force between protons and electrons, which means that they the protons tend to attract the electrons to the nucleus.
While a neutral atom presents the same number of protons and electrons, a cation is an ion with positive charge, which means it has lost one or more electrons. In a cation, the balance between protons and electrons doesn't exist anymore: now, there is more positive than negative charge (more protons than electrons), and the overall attractive force that the protons have for the electrons is increased. As a result, the electrons stay closer to the nucleus and the radius of a cation is smaller than the neutral atom from which it was derived.
On the other side, anions present negative charge, which means they have received electrons. Similarly to cations, the balance between protons and electrons doesn't exist anymore, but in this case, there are more electrons than protons. In an anion, the overall attractive force that the protons have for the electrons is decreased. As a result, the electrons are "more free" to move and, as they are not so attracted to the nucleus, they tend to stay farther from the positive nucleus compared to the neutral atom - because of this, the radius of an anion is larger than the neutral atom from which it was derived.
Covalent bond is a type of chemical bond which is formed as a result of sharing of electron pairs among the elements that are involved. The structure of the covalent bond is affected by the electronegativity of the elements involved. The molecules joined by covalent bond range in size from very small to very large polymers. There are different types of structures for covalent substances, these include: macromolecular substances, molecular substances and giant covalent structures. Strong bonds hold individual molecules together but there are negligible forces of attraction among them.
Answer:

Explanation:
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In this case, it is widely known that when measurements with different significant figures are put under mathematical operations, the final result must be displayed with the same amount of significant figures of the shortest measurement, thus, due to the fact that 5.5 g has two significant figures only the result is consequently shown with two significant figures as well as shown down below:

By rounding the first six to seven due to the fact that the next six is greater than five, according to rounding rules, the result is:

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Answer:
Potential energy is the energy stored within an object, due to the object's position, arrangement or state. Potential energy is one of the two main forms of energy, along with kinetic energy.
Explanation:
Answer : The freezing point of the solution is, 260.503 K
Solution : Given,
Mass of methanol (solute) = 215 g
Mass of water (solvent) = 1000 g = 1 kg (1 kg = 1000 g)
Freezing depression constant = 
Formula used :

where,
= freezing point of water = 
= freezing point of solution
= freezing point constant
= mass of solute
= mass of solvent
= molar mass of solute
Now put all the given values in the above formula, we get

By rearranging the terms, we get the freezing point of solution.

Therefore, the freezing point of the solution is, 260.503 K