Correct answer: has a completely filled outermost shell
Atoms of the element with complete outermost shells are stable. So, in order to attain stability the atom either loses electrons or gains electrons to completely fill the outermost shell. The stable electronic configuration for the s and p-block elements is exhibited by the noble gases or the group 8 elements. All the unstable atoms try to attain the electronic configuration of the nearest noble gas with completely filled outermost shell.
Divide 1.25/3.93 and then multiply by 100 to get the percent. This equals 31.81%
If you mean hydrate as in <em>MgSO4 · 7H2O, </em>then simply find the molar mass of each element you see.
For the example above, that means you would add the molar mass (found on the periodic table) of Mg, then S, then 4(O), 14(H), and 7(O).
The results would be your molar mass for the hydrate.
I hope this is what you meant by your question!
The answer is A. It is an alkyn. There is a triple bond