Question

Borul (Z-5) are doi izotopi naturali.Primul are numarul de masa 10u.a.m. si o concentratie in natura de 16,6%,iar celalalt are masa de11 u.a.m. Afla:
a)cati protoni si neutroni sunt in fiecare izotop.
b)masa atomica relativa a borului.

Answer 1

protoni 5p+ (Z=5)
a) A=Z+N          A=Z+N
   N=A-Z            N=A-Z
   N=10-5           N=11-5
   N=5               N=6
b) A=C1/100xA1+C2/100xA2
A=19,6/100x10+80,4/100x11 
A=0,196x10+0,804x11
A=19,6+8,844
A=10,804