Question

which of these elements forms ions with the same charge as radium ion? choose 1 answer: a oxygen b calcium c rubidium d iodine

Explanation:

Radium (Ra) is in Group 2 of the periodic table and forms a +2 ion by losing 2 electrons. Calcium (Ca) is also in Group 2 and forms a +2 ion in the same way. Oxygen forms a -2 ion, rubidium forms a +1 ion, and iodine forms a -1 ion.

Answer:

B. calcium