A negative ion of an atom element X has 18 electrons and 16 protons . Calculate the number of electrons and protons in its corresponding atom . Also calculate the number of nuetrons , if the mass number is units than double the number of protons.

Explanation

16 protons means that the atomic number of the element (X) is 16 . That is the electronic configuration is , 2 , 8 , 6 . It has to gain two electrons to attain octet configuration . Hence , the dinegative ion possesses 18 electrons.
`(X^(-2))=16+2=18`.
Mass number = 2+ 2 (number of protons)
= 2 + 2 (16) = 34
`:.:.` Number of neutrons = 18