when thorium(atomic number 90) emits a beta minus particle, theresulting nucleus has atomic number...?

Question

when thorium(atomic number 90) emits a beta minus particle, the resulting nucleus has atomic number
a) 88
b) 89
c) 90
d)91

Answer 1

d. 91 is the correct answer. A beta particle is an electron emitted by the nucleus. A neutron has given off an electron and became a proton. Atomic number is the number of protons in the nuclei, since the number of orbital electrons to balance them will be same. Thus the atomic number goes up by +1 and becomes 91 in this case.

Answer 2

C) 90 A beta particle is an electron,and since the atomic number has nothing to do with the number of electrons orbiting the nucleus,the AN remains at 90

Answer 3

89

Answer 4

89