Question

Что надо делать если даны элементы с непостоянной валентностью? Например FeCl

Answer 1

Ну и ? Если FeCl3 значит железо проявляет амфотерные свойства и может реагировать как и с щелочами так и кислотах .
А если например FeCl2 значит металл проявляет основные свойства то он может реагировать только с кислотами . 
Поясняй вопрос правильнее 

Answer 2

What to do with elements of variable valency?

When dealing with elements that have variable valency, such as FeCl, there are a few steps you can take to determine the valency of the element and balance the chemical equation:

1. Identify the element: In this case, the element is iron (Fe).

2. Determine the possible valencies: Iron can have multiple valencies, including +2 and +3.

3. Identify the other element or compound involved: In this case, it is chlorine (Cl).

4. Determine the valency of the other element or compound: Chlorine typically has a valency of -1.

5. Use the crisscross method: The crisscross method involves crossing the valencies of the elements and using them as subscripts to balance the charges. In this case, since chlorine has a valency of -1 and iron can have a valency of +2 or +3, we can write two possible formulas:

- FeCl2: In this case, the valency of iron is +2, and the valency of chlorine is -1. The charges balance out, resulting in a neutral compound. - FeCl3: In this case, the valency of iron is +3, and the valency of chlorine is -1. Again, the charges balance out, resulting in a neutral compound.

6. Verify the balanced equation: To verify the balanced equation, you can check that the charges on both sides of the equation are equal. For