Alcl3 is lewis acid. explain how?

 For AlCl3  to be a Lewis acid, it would have to react in such a way that it accepted a lone pair from some other atom or molecule from a Lewis base.AlCl3  has an electron-deficient aluminum atom. It has only six electrons in its valence shell. It readily accepts electrons from other atoms, in an attempt to get a full valence shell of eight electrons.

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