Answer:
B.) Oxygen is usually -2
Explanation:
Hydrogen is usually +1.
A pure group 1 element is not always +1.
A monoatomic ion can be a range of numbers. However, it must be a charge other than 0.
You should read up on Proust's law, better known as the Law of Definite Proportions. This is a chemical law that defines your question more generally, on why the ratio of elements and ions are always fixed.
Basically, this compound Magnesium(II) Chloride is MgCl2 because it has the same number of protons, neutrons, and electrons all the way. This defines the properties of the compound or atom.
PbCl2 would not dissolve because it is insoluble based on the solubility rules for substances that will dissolve in water. This compound would instead form a solid precipitate at the bottom of the container.
I would say D. Hope I helped, sorry if I didn't. :)
Answer:
Your notation is a bit confusing, let me write it more clearly.
Explanation:
( Temperature in °F − 32) × 5/9 = Temperature in °C