If the element has a charge of +2 it has lost two electrons giving it an overall positive charge making it a cation. In order to find the number of electrons, take the elements atomic number and subtract two since it lost two electrons
your answer will be :
B. <u>Na has a lower</u> <u>electronegativity than H</u>
because Na belongs to alkali metals which are least electronegative (most electro positive) but hydrogen is a non metal, it has higher electronegativity as compared to metals like Sodium (Na).