Shielding electrons are the electrons in the energy levels between the nucleus and the valence electrons. They are called "shielding" electrons because they "shield" the valence electrons from the force of attraction exerted by the positive charge in the nucleus. Hope this helps!!
5 i believe the right answer
<span>after the 1940, the infention of : PASTEURIZATION permitted wines to be produced in places where climate was not ideal for wine production
after pasteurization process, all the microbes that exist within the wine are eliminated, which will prevent it from rottening. This make it possible to store wine for a long period of time even thought it's not in the harvesting climate</span>
The law of conservation of mass dictates that the total mass of reactants must be equal to the total mass of the products. Thus:
mass(MgO) = mass(Mg) + mass(O)
mass(MgO) = 24 + 16
mass(MgO) = 40 g
The third option is correct.