CT: Mg3(XOy)2
theo đề ta có: A = 131.H2
\(\Rightarrow72+2X+32y=262\)
\(\Leftrightarrow2X+32y=190\)
\(\Leftrightarrow X=95-16y\)
biện luận:
\(+y=1\Rightarrow X=79\left(loai\right)\)
\(+y=2\Rightarrow X=63\left(loai\right)\)
\(+y=3\Rightarrow X=47\left(loai\right)\)
\(+y=4\Rightarrow X=31\left(lay\right)\)
vậy X là photpho
CT: Mg3(PO4)2