Henri Becquerel
A) discovered radium and polonium.
B) discovered radioactivity.
C) observed back-scattering from nuclei.
D) invented the particle detector tube.
E) proposed the tiny central nucleus idea.
Question 2Which uranium isotope has the largest cross section for slow neutrons?
A) U-236
B) U-238
C) U-237
D) U-235
E) U-239
Question 3Marie & Pierre Curie
A) discovered radioactivity.
B) proposed the plum-pudding model.
C) proposed the tiny central nucleus idea.
D) observed back-scattering from nuclei.
E) discovered radium and polonium.
Question 4Which Uranium isotope is the most commonly occurring isotope?
A) U-235
B) U-236
C) U-237
D) U-238
E) U-239
Question 5When a + particle is emitted from an unstable nucleus, the atomic number of the nucleus
A) increases by 1.
B) does not change.
C) decreases by 1.
D) increases by 2.
E) decreases by 2.
Question 6When a neutron is emitted from an unstable nucleus, the atomic mass number of the nucleus
A) does not change.
B) decreases by 2.
C) decreases by 1.
D) increases by 2.
E) increases by 1.