When you go looking for new elements, you already know how many protons they are going to have. It's a matter of finding the new element, making it, or detecting decay products that could only have come from the new element. This is a tricky process because the higher atomic weight elements are difficult to produce and very, very short-lived. It's rare for new elements to be discovered, so I'm excited that a team of Russian and American scientists report that they have created 6 atoms of element 117. Atoms of the new element were produced by firing atoms of calcium (atomic number 20) at a berkelium target (atomic number 97) to produce atoms with 117 protons.
At this time, no 'real' name for element 117 has been proposed, so you can call it element 117 or by its placeholder name, ununseptium (which means 117). Names are proposed for elements only after their existence has been confirmed by a second source. The New York Times has more details about the discovery or you can read the report of the element's production in Physical Review Letters.