One that has a constant temperature, that's even throughout the entire object. You didn't list down the choices, but whatever that fits this criteria is the correct answer. Maybe, if you comment down the choices; I'll tell you the correct ones.
Answer:
Multiply the element's atomic mass by the number of atoms of that element in the compound. This will give you the relative amount that each element contributes to the compound. For hydrogen chloride, HCl, the molar mass of each element is 1.007 grams per mole for hydrogen and 35.453 grams per mole for chlorine.
Largest to smallest: barium, calcium, selenium, oxygen
Option A is correct answer.
According to octet rule, atoms have tendency to lose, gain and share electrons to complete its octet i.e. eight valence electrons are surrounded to the atom.
Since, sulphur contains six valence electrons and two chlorine atoms are present in the reaction having seven valence electrons. Thus, to complete their octet, chlorine shares a pair of electrons with the sulphur atom.
The mass number is protons and neutrons. So I think it’s false