There isn't a single chemical formula for "metal" because metals are a broad category of elements.

Here's why:

* Metals are a group of elements: The periodic table has a large section dedicated to metals. Each metal has its own unique symbol and atomic number.

* Each metal has its own formula: For example, the chemical formula for sodium is Na, for iron is Fe, for gold is Au, and so on.

Instead of a single formula, you can represent metals in general ways:

* M: Sometimes you'll see "M" used as a general symbol for any metal in a chemical equation.

* Metal Symbol: When writing a chemical formula, you would use the specific symbol for the metal involved (e.g., FeCl2 for iron chloride).

Let me know if you have a specific metal in mind, and I can help you find its formula!