The atomic mass of an element is determined by the combined mass of its protons, neutrons, and electrons. In this case, you have mentioned an element with 1 proton, 1 electron, and 0 neutrons.
The atomic mass of an element is primarily determined by the sum of its protons and neutrons since electrons have negligible mass compared to them. Since there are no neutrons mentioned, and the element has 1 proton, the atomic mass of this element would be approximately equal to the mass of a single proton.
The mass of a proton is approximately 1.007 atomic mass units (amu). Therefore, the atomic mass of an element with 1 proton, 1 electron, and 0 neutrons would be approximately 1.007 amu.