The answer is 2.78 moles of Si
Elements Y and elements Z would have similar properties due to the fact that they both posses the same number of valence electrons. They both have a single valence electron that determines the corresponding elements bonding properties and the fact that it can either donate 1 valence electron to produce an ion that would be attracted to another atom, that is also an ion. Assuming that these elements are group 1 elements, they do not undergo in covalent bonding.
Moles = (6.74*10^23)/(6.02*10^23) =1.119 moles
1.119*44.09=49.36g
