Since the reaction shown in the question is an acid - base reaction in the Lewis sense; the Lewis acid here is AlCl3 while the Lewis base here is Cl^- .
<h3>What is a Lewis acid?</h3>
A Lewis acid is a substance that accepts electron pair while a Lewis base donates an electron pair.
Now consider the given reaction; AlCl3 +Cl^- ------> AlCl 4 ^-. The Lewis acid here is AlCl3 while the Lewis base here is Cl^- .
Learn more about acid - base reaction: brainly.com/question/14356798
Ch = sh = why and find the stuff
He thought elements that haven't been discovered belonged in the place of the gap. He could also use the atomic mass of the missing elements
