can I receive pending messages of whatsapp after I reactivate my account on new phone?
As long as you register your phone number on a new device within 45 days, you will receive all pending messages.

After 45 days, registering WhatsApp on a new device will be as if you never had WhatsApp before, no groups, no pending messages, no profile picture. 
(But you will still be able to retrieve your old messages from Google drive (not the pending ones though))