Zakaat - Rules and modern issues

Giving Zakaat as lump sum or in installments

Is it necessary that the whole amount Zakaat should be given in toto or can it be given in installments?  There are some details regarding this.  When 1 year passes on the wealth, Zakaat becomes Compulsory.  If the year has passed, then Zakaat should be given in full as soon as possible.  Giving it in installments will delay the giving of Zakaat.  On the contrary, if the year is about to end or if it is the beginning of the year, then in this case, until the end of the year, one can give Zakaat in as many installments as one wants to.