Study the history and structure of the atom, including the different experiments and models used to describe or determine the components that the atom consists of.

Welcome to your The History and Structure of the Atom

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Complete the following sentences:
Neutrons have a mass of
Protons have a charge of
The mass of an electron is
An electron has a charge of
The following shows an impression of what model of the atom proposed by J J Thomson in the late 19th century?
This model of the atom was based on the idea that an atom was made up of a positive medium, or space and with small distributed throughout it.
This model was accepted at the time because the neutron had not yet been discovered but the Greeks were aware that negative charges could be extracted from atoms. They knew this because of what area of physics?
Ernest Rutherford, with his PhD students decided to experiment with the model shown above to determine whether it gave rise to expected results.
What was the name of the experiment they performed?
After Rutherford and his colleagues conducted this experiment, what conclusion did they make about the nucleus of the atom?
Alpha particles have what charge?
What happened to the majority of the alpha particles as they were fired at the material?
Over 100 year ago, scientists thought the atom was like a 'plum pudding'.
The diagram below shows the plum pudding model of the atom.
The scientists knew that an atom has negatively charged particles. They also knew that an atom has no overall charge.
What did the scientists conclude about the charge of the 'pudding part' of the atom?
Americium-241 is an isotope of americium.
Which of the isotopes given in the table below is NOT an isotope of americium?

Give a reason for your answer.
The diagram shows a lithium atom.
What is the mass number of this lithium atom?
What is the atomic number of this lithium atom?
As an example, an isotope of this lithium atom would have how many electrons?
As an example a different isotope of this lithium atom would have how many neutrons?
The electrons in an atom orbit in different energy ______.
Some atomic nuclei are unstable and decay by emitting an alpha particle or a beta particle. Complete the symbols for an alpha particle and a beta particle.
A =
B =
C =
The diagram represents three atoms X, Y and Z:

Which two atoms are from the same element?

Complete the sentences:

In an atom, the number of electrons is equal to the number of .

All atoms of an element have the same number of .

Isotopes of the same element have different numbers of .

When an atom of a radioactive element emits alpha radiation, an atom of a different element is formed. A different element is formed because the radioactive element has lost .