Ответ:

Mr(Na2P)=23*3+31=100 ➡️ w(Na)= 69% w(P)=31%

Mr(PCl5)=31+35,5*5=208,5 ➡️ w(P)=15% w(Cl)=85%

Mr(P2O5)=31*2+16*5=142 ➡️ w(P)=44% w(O)=56%

Mr(PH3)=31+3=34 ➡️ w(H)=9% w(P)=91%