When hydrochloric acid reacts with sodium sulfide, hydrogen sulfide gas and sodium chloride are produced. how many moles of h2s will be generated by 2.56 moles of hcl? 2hcl + na2s → h2s + 2nacl

a 10 liters
b 0.1 liters
c 40 liters
d 20 liters

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.