Giải:
1. Theo đề ra, ta có:
\(\dfrac{NTK_X}{PTK_{H_2}}=15,5\)
\(\Leftrightarrow\dfrac{NTK_X}{2}=15,5\)
\(\Leftrightarrow NTK_X=15,5.2=31\left(đvC\right)\)
\(\Rightarrow X:P\)
2. \(CTTQ:X_2O\)
Theo đề ra: \(2X+16=62\Leftrightarrow X=\dfrac{62-16}{2}=23\left(đvC\right)\)
\(\Rightarrow X:Na\)