Answer:
Calcium
Explanation:
Since the element reacts with oxygen to form an oxide with the formula MO, the charge on the element is +2.
Also, since the oxide MO when dissolved in water is basic, the metal is an alkali earth metal.
From the above conditions;
The metal is not arsenic because arsenic is a metalloid has the following oxides As₂O₃ and As₃O₅ and are respectively amphoteric and acidic in nature
The metal is not germanium because is a metalloid and even though germanium oxide has the formula GeO₂, it is amphoteric.
The metal is not chlorine because chlorine is a non-metal
The metal is definitely calcium because calcium oxide has the formula CaO and calcium is an alkaline earth metal.
The metal is not selenium because selenium is anon-meal and its oxide has the formula Se0₂ and is acidic
