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7. |
The
periodic table of ancient times was composed of four elements. They
were ____________________, ____________________, ____________________,
and ____________________. The Greek philosopher who proposed this “periodic
table” was named ____________________. Aristotle, another Greek
philosopher, fully supported this model of matter. Not everyone at the
time agreed. The Greek philosopher ____________________ proposed that
all matter was made of tiny indivisible particles, which he called ____________________,
and empty space.
These ancient models of matter were based on thought
experiments rather than ____________________ knowledge. During the Middle
Ages, the ____________________ were determined to turn base metals into
____________________. They conducted experiments that opened the door
for more systematic experimentation and observation.
In 1803, an English schoolteacher named ____________________
came up with his atomic model, which consisted of the following ideas:
a.
b.
c.
d.
e.
This
model of the atom became widely accepted during the early part of the
nineteenth century. Further experiments conducted at the time led scientists
to think that the atom contained ____________________ particles. The
first subatomic particle to be discovered was the ____________________.
It was discovered by ____________________, who experimented using cathode
ray tubes. From the results of his investigations, he suggested that
the atom was a positively charged sphere with negatively charged particles
embedded in it. His model was known as the ____________________ model.
In 1911, ____________________ discovered that an atom contains a positively
charged centre surrounded by empty space. The positively charged centre
is called a(n) ____________________, and it is composed of ____________________
and ____________________. The ____________________, discovered by ____________________,
carry no charge.
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8. |
Using
the five ideas in an atomic model, read the following statements. Below
each statement, write down the idea that best represents the statement.
a.
Water has a boiling point of 100°C, while ethanol boils at 78.3°C.
b. Hydrogen peroxide is composed of two hydrogen
atoms and two oxygen atoms.
c. Sodium metal is composed of atoms that have
11 protons in their nucleus.
d. The oxygen atom in an oxygen molecule contains
eight protons in its nucleus. When oxygen molecules combine with hydrogen
molecules, water molecules are produced. The oxygen atom in a water
molecule contains eight protons in its nucleus.
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