## Chemistry 9th Edition

a) Ra - Radium - Loses electrons - Forms cation - $Ra^{2+}$ b) In - Indium - Loses electrons - Forms cation - $In^{3+}$ c) P - Phosphorus - Gains electrons - Forms anion - $P^{3-}$ d) Te - Tellurium - Gains electrons - Forms anion - $Te^{2-}$ e) Br - Bromine - Gains electrons - Forms anion - $Br^{-}$ f) Rb - Rubidium - Loses electrons - Forms cation - $Rb^{+}$
All metals lose their electrons to form cations (positively-charged ions) : (a) Radium (Ra) - Has 2 valence electrons, and thus loses 2, forming $Ra^{2+}$ . Also , Radium lies in group 2, where all elements have valency = 2+ (b) Indium (In) - Has 3 valence electrons, and thus loses 3, forming $In^{3+}$ . Also , Indium lies in group 13, where all elements have valency = 3+ f) Rubidium (Rb) - Lies in group 1, where all elements have valency = +1. Non Metals gain electrons to complete their octet to form anions (negatively-charged ions): (c) Phosphorus (P) - Has 5 valence electrons, hence gains 3 , forming $P^{3-}$ . Also , Phosphorus lies in group 15, where all elements have valency = 3- d) Tellurium (Te) - Has 6 valence electrons, hence gains 2 , forming $Te^{2-}$ . Also , Tellurium lies in group 16, where all elements have valency = 2- e) Bromine (Br) - Has 7 valence electrons, hence gains 1 , forming $Br^{-}$ . Also , Indium lies in group 17 (Halogens) , where all elements have valency = 1-