Chemistry: Atomic Theory Quiz 1a

A positively charged subatomic particle is a proton. Protons are found in the nucleus of an atom and have a positive charge. They are one of the fundamental particles that make up an atom, along with neutrons and electrons. Protons have a mass number of 1 and an element number that determines the type of element they belong to.

Atoms with the same number of protons but different numbers of neutrons are called isotopes. Isotopes have the same atomic number (number of protons) but different mass numbers (sum of protons and neutrons). This means that isotopes of an element have the same chemical properties but different physical properties, such as atomic mass. Isotopes can have different stability and may undergo radioactive decay.

Democritus is the correct answer because he was the first to propose the idea of atoms. He believed that atoms were indivisible and indestructible particles that make up all matter. By comparing atoms to tiny rocks, he was emphasizing their solid and fundamental nature. Thomson, Bohr, and Dalton also made significant contributions to atomic theory, but Democritus was the first to suggest the existence of atoms.

The statement "electrons have the mass of 1 amu" is false. Electrons have a much smaller mass compared to protons and neutrons. In fact, the mass of an electron is approximately 1/1836 amu, which is significantly lighter than 1 amu.

An electron is a subatomic particle with no charge. It is negatively charged and orbits around the nucleus of an atom. Protons, on the other hand, carry a positive charge, while neutrons have no charge at all. The option "Some type of 'tron'" is not a valid subatomic particle and does not exist.