Question

what does the charge on the top right hand corner of the element tell us? the difference in the number of electrons. the valence shell is full. if it is reactive or stable. if it is a heavier isotope.

Explanation:

The charge on the top - right corner of an element indicates the difference between the number of protons and electrons. A positive charge means there are more protons than electrons (cation), and a negative charge means there are more electrons than protons (anion). This difference in electron number affects chemical reactivity and stability. The full - valence shell is related to the octet rule and not directly to the charge notation. Isotopes are related to neutron number differences, not charge.

Answer:

The difference in the number of electrons.