How many protons and electrons are present in each ion? sn2+, o2-
For Sn2+, the element symbol Sn stands for tin. The superscript 2+ indicates that the ion has a charge of +2. Since the charge is positive, it means the ion has lost electrons. Tin normally has 50 protons and electrons. So, when it loses 2 electrons, it will have 50 protons and 48 electrons.
For O2-, the element symbol O stands for oxygen. The superscript 2- indicates that the ion has a charge of -2. Since the charge is negative, it means the ion has gained electrons. Oxygen normally has 8 protons and electrons. So, when it gains 2 electrons, it will have 8 protons and 10 electrons.