Laura Robson (ojoibi 21 January 1994) je agba tenis ara Britani.ItokasiAwon agba tenis ara Britani.. 
Iye àwọn nùkle (prontons ati neutrons) ninu Nurau ní nọmba àkójọ, and each ìsọtope of a given element has a different mass number.For example, carbon-12, carbon-13 and carbon-14 are three isotopes of the element carbon with mass numbers 12, 13 and 14 Ẹ̀bictivelyly 