In an atom the nucleus has an overall positive charge as it contains the protons.
Every atom has no overall charge (neutral). While atoms do contain charged particles, they have the same number of positive protons as negative electrons( for example a sodium atom has 11 electrons which are of negative charge and 11 protons which are of positive charge).
These opposite charges cancel each other out making the atom neutral.
Result: Nucleus is the overall positive charge of an atom.
