Question

4×10^22 atoms of an element weigh 12g . Gram atomic weight of element

Answer 1

180.9479

Note that 4 x 10²² atoms = 0.066 mol (use Avogadro’s number).

Divide this into 12 g to get the number of grams per mole.

Use a periodic table to find the element with the corresponding atomic weight.

the amount of one gram atomic weight (M gram) of an element contains an Avogadro number of atoms, NA = 6.023 x 10^23 atoms per gram atom. Therefore 4 x 10^22 atoms represent (4 x 10^22) / (6.023 x 10^23) = 0.066412 gram atom of any element. Dividing 12 gram by 0.066412 leads to the desired gram atomic weight M = 180.69 gram. The nearest value corresponds to Tantal, the official value of the gram atomic weight of Ta being 180.9479