Question

An atom of radium (Ra) forms a monatomic ion.

Which ion does it most likely form?
a- Ra2-
b- Ra-
c- Ra2+
d- Ra+

Answer 1

The ion that an atom of radium (Ra) most likely forms is Ra2+. So the correct option is c.

Step-by-step explanation:

The ion that an atom of radium (Ra) most likely forms is c- Ra2+.

When an atom forms an ion, it gains or loses electrons to achieve a full outer shell and become more stable. Radium belongs to Group 2A of the periodic table, meaning it has 2 valence electrons. To achieve a full outer shell, it loses 2 electrons and becomes a Ra2+ ion.

For example, the electron configuration of a Ra2+ ion is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2, which is the electron configuration of a noble gas, xenon (Xe). This configuration is stable and satisfies the octet rule.

Answer 2

The atomic number of the element Radium (Ra) is 88. It is an alkaline earth metal. Electronic configuration of Radium (Ra) will be [Rn]7s^{2}[Rn]7s

2

It belongs to the group IIA of the periodic table. Alkaline earth metals that belong to the group IIA of the periodic table lose the valence electrons to form a +2 ion.

Therefore, Radium with an electronic configuration of [Rn]7s^{2}[Rn]7s

2

will lose the two 7s electrons to form the cation with +2 charge.