Why are salts, such as sodium chloride made of elements found on opposite ends of the periodic table?

a. elements on the far left tend to form positive ions while those on the right tend to form negative ions.
b. elements on opposite ends of the periodic table have similar arrangements of electrons.
c. elements on the far left tend to form negative ions while those on the right tend to form positive ions.
d. elements on opposite ends tend to share a pair of electrons with each other.

I think A

A is correct. b is not true, c is not true, d is not true.

Thanks and I have one other question
Why is sugar not infinitely soluble in water?
a. when you mix enough sugar into water the solution eventually solidifies.
b. because of the strong attractions that occur between sugar molecules.
c. because of the strong attractions that occur between water molecules.
d. because there is only so much space between water molecules for sugar molecules to fit.

Would it be D?

I don't like the question but I think D is the best answer. a isn't true, b is somewhat true, c is true but that isn't the reason, and d is true. So the least of the evils is d I think.

Thank you very much

You're welcome! I'm glad I could help. In the case of why salts are made of elements found on opposite ends of the periodic table, you are correct that option A is the correct answer. Elements on the far left tend to form positive ions, called cations, by losing electrons, while elements on the right tend to form negative ions, called anions, by gaining electrons. So when these oppositely charged ions come together, they form an ionic bond and create a salt.

For the question about why sugar is not infinitely soluble in water, you are also correct that option D is the best answer. While options B and C mention strong attractions between sugar or water molecules, they do not fully explain why sugar is not infinitely soluble. Option A is not true because sugar does not solidify when it is fully dissolved in water. Option D is the most accurate explanation, as there is a limited amount of space between water molecules for sugar molecules to fit when dissolving, leading to the saturation point where no more sugar can dissolve.