Why sheilding effect make cation formation easy

answer:

the shielding effect reduces the ionization energy and so makes cation formation easier.

explanation: attractive force between the valence electron and the nucleus of the atom. if the electron has a high force of attraction with the nucleus, it is very difficult to remove them

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