<u>Answer:</u> The element represented by M is Strontium.
<u>Explanation:</u>
Let us consider the molar mass of metal be 'x'.
The molar mass of MO will be = Molar mass of oxygen + Molar mass of metal = (16 + x)g/mol
It is given in the question that 15.44% of oxygen is present in metal oxide. So, the equation becomes:

The metal atom having molar mass as 87.62/mol is Strontium.
Hence, the element represented by M is Strontium.
The name of the ion is chloride.
To name a <em>monatomic anion</em>
• <em>Drop the ending</em> of the element name (chlor<u>ine</u> → chlor)
• <em>Add the ending</em> <em>ide</em> (chlor + ide → chloride)