Playstation memory card question...?

May be...

will a playstation 1 memory card work on a playstation 2 slim system as long as the game being played is a Playstation 1 game?

I think so. Actually, it will work.

Yeah. That's actually how it works. You need a PS1 memory card for a PS1 game and a PS2 memory card for a PS2 game. However, you can't use a PS1 memory card for PS2 games or a PS2 memory card for PS1 games.

PS1 games can be stored only on PS1 cards due to the different architecture (PS1 uses old blocks system, while PS2 already uses standard memory, measured in MB).

Yea to save ps1 games when playing on ps2 u need a ps1 mem card, and yea it works on the slim ps2.