What particle in an atom is positively charged and located in the nucleus?

The positively charged particle in an atom located in the nucleus is a proton. Protons are one of the fundamental constituents of atomic structure, along with neutrons and electrons. Each proton carries a positive electrical charge, which is essential for determining the atom's overall charge and its chemical properties.

The presence of protons in the nucleus plays a critical role in defining the atomic number of an element, which in turn determines which element it is. For example, an atom with one proton is hydrogen, while an atom with six protons is carbon. The positive charge of protons helps to attract negatively charged electrons, balancing the atom's charge and contributing to its stability.

In contrast to protons, neutrons are neutral particles found in the nucleus but do not have any charge, while electrons are negatively charged particles that orbit the nucleus. Photons are not particles that make up atoms; they are fundamental particles of light and electromagnetic radiation, playing a different role in physics and the interactions of energy rather than the structure of atoms.

Therefore, the proton is the correct answer regarding the positively charged particle located in the nucleus of an atom.