Question

which metal in period 5 is very reactive and has two valence electrons in each atom?
○ rubidium (rb)
○ strontium (sr)
○ zirconium (zr)
○ silver (ag)

Explanation:

• Rubidium (Rb) is in Group 1 (1 valence electron).
• Silver (Ag) has a more complex electron configuration and is not highly reactive in the sense of easily losing two valence electrons.
• Zirconium (Zr) is a transition metal with a different electron - configuration pattern.
• Strontium (Sr) is in Group 2. Elements in Group 2 have 2 valence electrons. As we move down the group in the periodic table, the reactivity of Group 2 elements increases. Strontium is in Period 5.

Answer:

strontium (Sr)