Zinc is put in concentrated sodium hydroxide

How many liters of hydrogen gas will be produced at stp from the reaction of 7.179×10^23 atoms of magnesium with 54.219g of phosphoric acid (h3po4) the equation is 3mg + 2h3(> mg(po4)2+3h2

When the mercury level in a barometer decreases that atmospheric pressure has

Suppose you discovered a new element with 120 protons and 2 electrons in its outer level . i'm what group does this new element belong? what properties would you expect it to have