Atom has 4 electron layers and 7 electrons in the outer energy layer.

The number of electron layers and the number of electrons (elementary particles) on the outer electron layer of a chemical element can be easily determined by its location inside the DI Mendeleev’s table. The serial number of the period of a chemical element corresponds to the number of electron layers of the atom. The number of electrons located on the external electronic level corresponds to the group number. Manganese (Mn), an element of the seventh group, belonging to the 4th period of the DI Mendeleev’s table, has four electronic layers and seven electrons on the outer electronic level.