A10.0-gram sample of which element has the smallest volume at stp?
(1) aluminum (3) titanium
(2) magnesium (4) zinc

Since all of these elements are under the same conditions, volume only varies based on the number of atoms present. You can find the number of atoms in a given sample by dividing the weight of the sample by the molar mass.

Aluminum has a molar mass of 26.9 so 10/26.9 = .371 moles

go on to get Ti= 10 /  47.88 =.209 moles

Mg = 10.0 / 24.3 = 0.412 moles

Zn = 10 / 65.37 = .153 moles

Since there are less moles of Zn, it has the smaller volume at STP than the other elements.