According to your opinion, is dividing a work on the two periods better than one period ?

May be some jobs need that dividing a work to periods

Yeah It can be provided it is6040 ration basis . 

Encouraging Employee to work hard for first60 percent work 

so that40 percent in next half can be achieved quickly by virtue the speed done in first half. 

and so one can offer a party get together to make relationship with Employee and more cohesive ambiance

Sure, it makes the job less cumbersome

It is always better to have a break in between work. Helps in getting re-energized and bring back focus.