For the main group elements( excluding the transition elements) , is it necessary to memorize the type of ion each element makes or could you predict the ion charge using a periodic table?

You can predict it based of the electronegativity

the catch is that the top numbers are atomic masses the bottom numbers are the numbers of protons and electrons in an uncharged atom. they are the number of that atoms as you would find them on the periodic table. further, the numbers on the left are used to determine the missing numbers on the right

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer

7is b8 is d9 is c10 is a11 is d