Uninzi lwee-elements endalweni lwenziwe ngee-atoms ezinamanani ee-neutrons awohlukenenyo okanye angafaniyo. I-isotope luhlobo lwe-element olunenani elithile lee-neutrons. Umzekelo, i-carbon inee-isotopes ezimbini ezingagungqiyo kwelo nani, ezi ke zii-isotopes ezizenzekelayo: i-carbon-12 (inee-neutrons ezi-6) ne-carbon-13 (ii-neutrons ezisi-7). I-Carbon-14 (nee-neutrons ezisi-8) yi-radioactive isotope e-carbon ezenzekelayo. Kwi-element nganye, ngaphandle kwe-Ununoctium, zimbini ii-isotopes ziyaziwa.