Which boxes show particle diagrams of elements?

Which boxes show particle diagrams of compounds? 

Helium does not react with anything at all. Atoms of helium do not combine with any other atoms. Which diagram best represents helium?

Oxygen gas is in the form of particles which have the formula ${\mathrm{O}}_2$. Which two diagrams show this arrangement? 

Carbon dioxide has the formula ${\mathrm{CO}}_2$, Which diagram could represent carbon dioxide?

Hydrogen atoms are smaller than any others. Which diagram could represent water? 

Which of the following could be the name of the substance in box? (a) nitrogen  (b)carbon monoxide (c) sulphur dioxide