Consider the XPS spectrum given to the right, collected using a $Mg{K}_{}$ source. Peaks $1$ and $2$ were used to determine a relative concentration of the two main elements within the materials as $50\%$ atomic fraction each. Given this information, answer the following questions:

$($a$)1\mathrm{.}0pt$ Identify all of the regular XPS peaks $(1-5)$ with respect to their source element and the nature of the detected electron $($i$.$e$.$ orbital$).$ Don't worry about the Auger peaks $(6$ and $7).$

$($b$)0\mathrm{.}5pt$ Based on the infor gathered in $($a$),$ what is the composition of the material?