Answer:
Option B. Rb⁺ and Sr²⁺
Step-by-step explanation:
From the question given above,
Rubidium (Rb) is located in group 1 Strontium (Sr) is located in group 2.
Group 1 element can only form ion by losing 1 electron. Thus, Rubidium (Rb) can form ion by losing it outmost electron (i.e 1) according to the equation below:
Rb —> Rb⁺ + e¯
Thus, Rubidium form ion as Rb⁺
Group 2 element can form ion by losing 2 electrons. Thus, Strontium (Sr) can form ion by losing it outmost electron(s) (i.e 2) according to the equation below:
Sr —> Sr²⁺ + 2e¯
Thus, Strontium form ion as Sr²⁺
SUMMARY:
Rubidium form ion as Rb⁺
Strontium form ion as Sr²⁺
Therefore, option B gives the correct answer to the question.