The 10.1 tablet charger
A little bit more information would have been nice e.g. charger models. 

Anyway since the phone charger isn't charging your tablet i suspect that the phone charger does not deliver enough power. The Samsung adaptive charger i know of does support up to 2A although the website only list support for new samsung smartphones. I guess it will not recognise your tablet as a fast charge compatible device and it will charge it with the standard usb 2 power (500 mA) which isn't enough. 

I recommend you to simply label your different charger to recognise them easier.