A team of Russian and American scientists have discovered a new heavy element, which they have given the temporary name Ununseptium with the symbol 'Uus' and contains 117 Protons and Electrons. As only a few atoms of ununseptium have ever been made, its reactivity with air is unknown. Elements like ununseptium are synthesized by bombarding more stable elements or their isotopes with isotopes of other elements. The collisions caused during this bombardment can cause heavier elements to emerge, albeit usually briefly. Scientists take advantage of the brief appearance of these elements to make as many observations about them as possible. Given that only a few atoms of a transactinide element are produced at any given time with this technique, you can imagine that the equipment involved is extremely precise and very expensive.