An ion corresponds to an atom that has gained or lost electrons. When an atom loses electrons it will have a positive charge, one for each electron lost. If the atom gains electrons it will have a negative charge, one for each electron it gains.
Now, whether an element loses or gains electrons depends on its valence electrons, generally when the valence number is less than 5 the element will tend to lose electrons and form a positively charged ion. If the element has more than 5 electrons, it will gain electrons and will have a negative charge.
Radium (Ra) is located in group II of the periodic table, so this element has 2 valence electrons. It means that the "Ra" will lose its valence electrons and the ion will have a positive charge +2.
Therefore, the answer will be: Ra2+
Answer:
Ra2+
uppercase R lowercase a superscript 2 plus end superscript