Which monatomic ions would you expect radium (z = 88) and selenium (z = 34) to form?

Radium belongs to 2nd group (Magnesium family) which means it will give +2 ion.
Ra2+

Selenium belongs to Oxygen family which means it will give -2 ion.
Se2-

Atomicity occurs to prevent updates of the database occurring only partially, which can cause greater problems than rejecting the whole series outright.some are monatomic, diatomic, triatomic etc because it shows the number of atoms. for example, monatomic means it contains only one atom.