It is rutherfordium number 104
octave
Some unknown prehistoric person.
Marguerite Perey, 1939
Roentgenium, element 111, named after the discoverer of the X-ray, Wilhelm Roentgen.
Copper was discovered thousands of years ago; it is not likely that you will find the name of the person who discovered it.
The first element to be discovered was probably copper or gold. They would have been discovered by hunter-gatherers or early farmers. Its discovery cannot be credited to any single person.
I guess the answer to this will vary for each person. But my choice will be CARBON.
Tin is in the group 14 (carbon group) of the periodic table.
Lead has been known since ancient times. The exact person who discovered it is unknown. It is a blue-white metal element.
Henning Brand was a German chemist. He is believed to be the first person to 'discover' an element. In 1669 he discovered phosphorous.
Protons were discovered when the nucleus of atoms were discovered. Electrons were already known about, so when the nucleus was discovered, it was known that it had to contain positively charged particles: protons. The nucleus was discovered by Ernest Rutherford by shooting alpha particles (helium nuclei, basically helium without the electrons) at a thin sheet of gold. Most of the alpha particles went straight through, but some if them were scattered. Rutherford deduced that these particles had hit something in the foil that didn't take up a large percentage of space: the nuclei of the gold atoms.
The element Rutherfordium (element 104) is named after Sir Ernest Rutherford who discovered the structure of the atom.