CHEMISTRY 11 – EARLY MODELS OF THE ATOM WORKSHEET
1) Match each scientist (Dalton, Thomson, Rutherford & Bohr) to the statements describing his
contribution to the atomic theory. Identify who was the first person to propose the idea or make the
discovery. Each scientist may be used more than once.
a) Atoms cannot be created, destroyed or divided into smaller particles. Dalton
b) Discovered the nucleus. Rutherford
c) Electrons occupy specific energy levels or shells. Bohr
d) Most of the mass of the atom is in the tiny, dense, positively charged nucleus. Rutherford
e) Most of the atom is empty space. Rutherford
f) Proposed the “billiard ball” model of the atom. Dalton
g) All matter is made of small particles called atoms. Dalton
h) All atoms of the same element are identical. Dalton
i) Atoms contain negatively charged particles. Thomson
j) The nucleus contains positively charged particles called protons and particles with no electric
charge called neutrons. Rutherford
k) Different elements combine together to form compounds. Dalton
l) Discovered the electron. Thomson
m) Electrons move around a central nucleus. Rutherford
n) Proposed the “plum pudding” model of the atom. Thomson
o) Atoms of one element are different from the atoms of other elements. Dalton
p) Electrons give off or absorb energy when they moved from one orbit to another. Bohr
q) Observed streams of negatively charged particles in gas discharge tubes. Thomson
r) Discovered the neutron. Rutherford
s) Compounds are created when atoms of different elements link together in specific ways. Dalton
t) Discovered the proton. Rutherford
u) The number of electrons surrounding the nucleus equals the number of protons in the nucleus.
Rutherford
