(a) Draw the structures of the following molecules: (i) N2O5 (ii) HClO4 (b) Explain the following observations: (i) H2S is more acidic than H2O. (ii) Fluorine does not exhibit any positive oxidation state. (iii) Helium forms no real chemical compound.

(i) The S-H bond is weaker than the O−H bond, meaning that H2S more easily donates a proton and is, therefore, more acidic. Water is amphoteric; it can act both as a proton donor (acid property) and as a proton acceptor (base property) (ii) Fluorine has the highest electronegativity on any of the elements, in order for it to get a positive charge, you would need another element with even higher electronegativity, which doesn't exist (iii) Because it has 2 electrons which fill up its electron shell, making it unreactive and stable.