Question

1. Aston’s measurements with mass spectrograph showed that the mass of the carbon-12 nucleus was ______________________the mass of 12 hydrogen nuclei.

   		slightly less than,
   		exactly equal to
   		slightly more than
   		none of this

10 points   

QUESTION 2

1. Aston’s work showed that nuclei in the middle of the periodic table_____________
   than the lightest and heaviest nuclei

   		are more loosely bound
   		are more tightly bound
   		have more isotopes
   		are more abundant

10 points   

QUESTION 3

1. As a result of Aston’s work, we know that two nuclei are isotopes when they have

   		the same atomic weight but different atomic numbers
   		the same atomic number but different atomic weight
   		the same atomic number and the same atomic weight
   		different atomic  weights and different atomic numbers

10 points   

QUESTION 4

1. _________________ discovered the positron

   		Carl Anderson
   		Otto Hahn
   		Enrico Fermi
   		Arthur Dempster

10 points   

QUESTION 5

1. Mass of positron is the same as mass of

   		proton
   		neutron
   		alpha-particle
   		electron

10 points   

QUESTION 6

1. _______________    discovered neutron .

   		the Joliot-Curies
   		Niels Bohr
   		James Chadwick
   		Otto Hahn

10 points   

QUESTION 7

1. ________________ was the first to make a theoretical model of the nucleus using the idea of a liquid drop.

   		Carl Anderson
   		Ernest Rutherford
   		James Chadwick
   		Niels Bohr

10 points   

QUESTION 8

1. Who discovered artificial radioactivity?

   		the Joliot- Curies
   		Otto Hahn
   		Enrico Fermi
   		Niels Bohr

10 points   

QUESTION 9

1. In 1935, Fermi discovered that hydrogen could slow neutrons down and thereby increase their capture cross section for many nuclei. This process of slowing neutrons down is called

   		neutron decay
   		neutron moderation
   		neutron bombardment
   		induced ionization

10 points   

QUESTION 10

1. Who discovered Uranium-235?

   		Carl Anderson
   		Otto Hahn
   		Enrico Fermi
   		Niels Bohr

10 points   

QUESTION 11

1. When Otto Hahn discovered an isotope of barium resulting from his bombardment of uranium by neutrons, he referred to it as his “barium fantasy” because

   		barium is transuranic element
   		barium is chemically unstable
   		barium’s atomic number was far from uranium’s

Answer 1

Answer 1- slightly more than

Answer 2- are more tightly bound

Answer 3- the same atomic number but different atomic weight

Answer 4- Carl Anderson

Answer 5- electron

Answer 6- James Chadwick

Answer 7- Niels Bohr

Answer 8- the Joliot- Curies

Answer 9- neutron moderation  

Answer 10-  Otto Hahn ( but originally it was discovered by Arthur Jeffrey Dempster).

Answer 11-  barium’s atomic number was far from uranium’s