An atom of an element has to go electrons in the first level and five on the second level what is this element

Plz choose one of the compounds from the table and explain how you know the numbers of atoms in your formula. is it possible for two different compounds to be made from the exact same two elements? why or why not? with a limited number of elements (less than 120 are known), does this mean we also have a small number of compounds or do we have a large number of compounds in this world?

In an exothermic reaction the bonding energy of the product is: less than the reactants same as the reactants greater than the reactants dependent upon the presence of a catalyst

A1.5l container holds p.50 grams of an unknown gas at a pressure of 0.44 atm and a temperature of 50.c what is the molar mass of the unknown gas