Pls help with my fianals​

When will le chatelier's principle come into effect? at the beginning of a reaction, when there are only reactants when a reaction has reached chemical equilibrium when a catalyst is added to a reaction mixture when a reaction is occurring but not yet at equilibrium

Which compound contains both ionic and covalent bonds? a) hbr b)cbr4 c)nabr d) naoh

The difference between the atomic number of an element and the element’s atomic mass is the number of ions.