Sec. 2-1. Rules of descent and distribution. The intestate real and personal estate of a resident decedent and the intestate real estate in this State of a nonresident decedent, after all just claims against his estate are fully paid, descends and shall be distributed as follows:
(a) If there is a surviving spouse and also a descendant of the decedent: 1/2 of the entire estate to the surviving spouse and 1/2 to the decedent's descendants per stirpes.