There will be 25 protons. The element with atomic number 25 is Manganese (Mn).
In science, we differentiate between different elements by the number of protons that they possess. To make it easier, we added symbols to these numbers so we could easily speak about them. For example:
So if it is given that an element has atomic number 25, we can easily say that it must have 25 protons, because that is by definition the way we define the different elements.
To find the element with 25 protons you can look at the periodic table. The element with atomic number 25 is Manganese (Mn).