my 25 months son not taking nap fm 7am to 7.30pm

I.am a desperate and worried mum my son not taking any nap after he wakes up at 6am till 730pm since one week ago. He only sleep 9 to 10 hours a day It is normal or is there any reasons ?really at my wiit end and keep worry he is not getting sleep for mental and physical development at this age. Any one experienced this? any thing I can do scientifically or religiously . Hope this is just a phase I