1. Who first proposed that matter is made of indivisible particles called atoms?

a) J.J. Thomson
b) Ernest Rutherford
c) Niels Bohr
d) Democritus

2. What does the Greek word "atomos" mean?

a) Small sphere
b) Can't be split
c) Tiny particle
d) Energy level

3. Which scientist discovered the electron?

a) Ernest Rutherford
b) Niels Bohr
c) J.J. Thomson
d) Democritus

4. Which scientist discovered the nucleus and the proton?

a) J.J. Thomson
b) Niels Bohr
c) Ernest Rutherford
d) Democritus

5. Who proposed that electrons orbit the nucleus in shells or energy levels?

a) Ernest Rutherford
b) J.J. Thomson
c) Niels Bohr
d) Democritus

6. What is the approximate radius of an atom?

a) 1 mm
b) 1 x 10^-6m
c) 1 x 10^-10 m
d) 1 x 10^-9 m

7. Where are the protons and neutrons located in an atom?

a) Electron shells
b) Nucleus
c) Outside the atom
d) In empty space

8. What is the relative charge of a proton?

a) -1
b) 0
c) +1
d) +2

9. What is the relative charge of an electron?

a) +1
b) 0
c) -1
d) +2

10. What is the relative mass of a neutron?

a) 0
b) 1
c) 2
d) 1/2000

11. Which subatomic particle has the smallest mass?

a) Proton
b) Neutron
c) Electron
d) Nucleus

12. Where is most of the mass of an atom concentrated?

a) Electron shells
b) Nucleus
c) In the empty space within the atom
d) Outside the atom

13. What is the approximate size of the nucleus compared to the size of the atom?

a) 1/100th
b) 1/1000th
c) 1/10 0000th
d) 1/10 000th

14. Atoms are mostly:

a) Solid spheres
b) Empty space
c) Liquid
d) Made of neutrons.

15. What is the actual mass of a proton in Kg?

a) 9.11 x 10^-31
b) 1.67 x 10^-27
c) 0
d) 1