Explain the formation of the compound formed by two elements with Z = 20 and Z = 17 .

Explanation

`{:("Element","Atomic number","Electronic configuration"),(" "Ca," "20," "2_(,)8_(,)8_(,)2),(" "Cl," "17," "2_(,)8_(,)7):}`
Ca loses two electrons to attain octet while Cl gains an electron to attain octet. Hence , the formula of the compound is
`Ca^(+2)Cl^(-1)`
`CaCl_(2)`