All atoms are inherently neutral. The atoms of all elements have a fixed number of protons that is equal to the element's atomic number. The protons are positively charged; atoms also have an equal number of electrons each of which is negatively charged and has a charge equal in magnitude to that of the proton.
Aluminum has an atomic number of 13. It has 13 electrons in its electron shell. Aluminum is an electropositive element, its reacts with electronegative elements to form stable chemical compounds. The three electrons in the outermost shell are donated to atoms or ions that can accept electrons. This leaves aluminum with a stable electron configuration that is similar to the nearest Noble gas Neon.
Aluminum is not neutral because in order for an element to be neutral it has to have a noble gas configuration (8 valence electrons). Now it can have a pseudo noble gas configuration to be considered neutral by naturally it inst since it has 3 valence electrons.