What is the atomic radius and melting point of this formula? c7h8n4o2

Can someone me with questions 15 to 17 plz.

What is the atomic number of an atom that has 6 protons

Consider the following reaction at equilibrium: c(s)+h2o(g)⇌co(g)+h2(g) predict whether the reaction will shift left, shift right, or remain unchanged upon each of the following disturbances. a) c is added to the reaction mixture. b) h2ois condensed and removed from the reaction mixture c) co is added to the reaction mixture d) h2 is removed from the reaction mixture.