Metal $$\mathrm{M}$$ crystallizes into a fcc lattice with the edge length of $$4.0 \times 10^{-8} \mathrm{~cm}$$. The atomic mass of the metal is ____________ $$\mathrm{g} / \mathrm{mol}$$. (Nearest integer)

$$\left(\right.$$ Use : $$\mathrm{N}_{\mathrm{A}}=6.02 \times 10^{23} \mathrm{~mol}^{-1}$$, density of metal, $$\mathrm{M}=9.03 \mathrm{~g} \mathrm{~cm}^{-3}$$ )

An element M crystallises in a body centred cubic unit cell with a cell edge of $$300 \,\mathrm{pm}$$. The density of the element is $$6.0 \mathrm{~g} \mathrm{~cm}^{-3}$$. The number of atoms present in $$180 \mathrm{~g}$$ of the element is ____________ $$\times 10^{23}$$. (Nearest integer)

Metal deficiency defect is shown by Fe_0.93O. In the crystal, some Fe²⁺ cations are missing and loss of positive charge is compensated by the presence of Fe³⁺ ions. The percentage of Fe²⁺ ions in the Fe_0.93O crystals is __________. (Nearest integer)

In a solid AB, A atoms are in ccp arrangement and B atoms occupy all the octahedral sites. If two atoms from the opposite faces are removed, then the resultant stoichiometry of the compound is A_xB_y. The value of x is ____________. [nearest integer]