When 25.6 grams of valence metal oxide 2 interacts with hydrogen, 3.6 grams of water vapor are formed.

We write down the reaction equation.
MeO + H2 = Me + H2O.
x + 16 g / mol 18 g / mol

Using the reaction equation, we find the molar mass of the metal. Let’s denote the molar mass of the unknown metal through x.
Next, we calculate the molar mass of the metal oxide and water.
M (MeO) = (x + 16) g / mol.
M (H2O) = 1 × 2 + 16 = 18 g / mol.
25.6 g MeO – 3.6 g H2O.
(x + 16) g / mol MeO – 18 g / mol H2O.
Find the unknown value of x.
(x + 16) × 3.6 = 25.6 × 18.
3.6 x + 57.6 = 460.8.
3.6x = 460.8 – 57.6.
3.6x = 403.2.
x = 403.2 ÷ 3.6 = 112.
The molar mass of the unknown metal is 112 g / mol. According to the periodic table, we find out that a metal that has a molar mass equal to 112 g / mol is called cadmium (Cd).
Answer: cadmium.