Ответ: ₉F¹⁹протонов 9нейтронов 19-9=10Δm = (9·1,00728а.е.м +10·1,00866а.е.м.) -18,9984а.е.м.= 19,15212а.е.м. -18,9984а.е.м =0,15372а.е.мЕ = 0,15372а.е.м.· 931МэВ =143,11МэВ