Answer:
Strontium
Step-by-step explanation:
The atomic number of strontium is 38.
It has 38 electrons.
It is alkaline earth metal. It has two valance electrons.
Strontium loses its two electrons and form cation with +2 charge.
Electronic configuration;
Sr₃₈ = [Kr] 5s²
The valance electrons present in 5s are lost by strontium atom and form Sr⁺² cation.
it is yellowish-white metal.
It is highly reactive.
It form salt with halogens.e.g
Sr + Br₂ → SrBr₂
IT react with oxygen and form oxide.
2Sr + O₂ → 2SrO
this oxide form hydroxide when react with water,
SrO + H₂O → Sr(OH)₂
With nitrogen it produced nitride,
3Sr + N₂ → Sr₃N₂
With acid like HCl,
Sr + 2HCl → SrCl₂ + H₂