I need the answer in English

We use the formula: $\text{Moles} = \frac{\text{Mass}}{\text{Molar Mass}}$

$$\text{Moles of Cu} = \frac{3.20 \text{ g}}{64 \text{ g/mol}} = 0.05 \text{ mol}$$

The reaction of P with $\text{Cu}^{2+}$ can be represented as:

$$2\text{P}(s) + n\text{Cu}^{2+}(aq) \to 2\text{P}^{n+}(aq) + n\text{Cu}(s)$$

Where $n$ is the charge of the P ion. The mole ratio of P to Cu is $2:n$.

$$\frac{\text{Moles of P}}{\text{Moles of Cu}} = \frac{2}{n}$$ $$\frac{0.03391 \text{ mol}}{0.05 \text{ mol}} = \frac{2}{n}$$ $$0.6782 = \frac{2}{n}$$ $$n = \frac{2}{0.6782} \approx 2.949$$

Rounding to the nearest whole number, $n = 3$.
Therefore, the charge of the metal ion P is $\boxed{\text{+3}}$.