Paying salary at the end of year

If we have an employee whose annual salary is 1,80,000 INR per annum.  Is it okay from income tax point of view if the salary is paid to him once at the end of year say on 31st March 2014 for whole of 2013-2014 ?

Or it's was mandatory to pay him every month for the months gone ?

Also, since the salary is below income tax slab of 200000 INR, is it mandatory for the employee to provide his PAN details ?

let me know.

Divya