The 10.1 tablet charger Does the 10.1 tablet have a special charger. 
The one for the phone says adaptive fast charging with a electric symbol. It doesn't appear to work properly on the tablet. The tablet shows a symbol with a red x in it whilst the special one for the tablet is plain and shows the correct symbol while charging. The 2 different chargers are a puzzle unless you are aware and use only the dedicated one which is nearly identical to the others. Thanks Samsung for this hidden tidbit.
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.