Download Structure of an Atom.pptx

Aim: What are the Parts of an Atom?
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Rings
• Electrons
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Nucleus
• Protons
• Nuetrons
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Particles that are smaller than the atom are
called subatomic particles.
The three main subatomic particles that form
an atom are protons, neutrons, and electrons.
The center of the atom is called the nucleus.
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Protons and neutrons make up the nucleus of an
atom.
All protons are identical to each other, and all
neutrons are identical to each other.
Protons have a positive electrical charge, so they
are often represented with the mark of a "+" sign.
Neutrons have no electrical charge and are said to
help hold the protons together (protons are
positively charged particles and should repel
each other).
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If all protons are identical and all neutrons
are identical, then what makes the atoms of
two different elements different from each
other?
For example, what makes a hydrogen atom
different from a helium atom?
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The number of protons and neutrons in
the nucleus give the atoms their specific
characteristics.
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The atomic nucleus is the densest part of any
atom. It is the area that contains the protons
and neutrons. In most atoms the nucleus
accounts for over 99% of the atom’s mass.
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Nucleus has a large mass
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Protons and neutrons
Nucleus has a small volume
Large Mass
= Very Dense!
Small Volume
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Rings have a small mass
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Electrons
Rings have a large volume
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Mostly empty space
Small Mass
= Not Dense
Large Volume
Electrons are the negatively charged particles
of atom. Together, all of the electrons of an atom
create a negative charge that balances the positive
charge of the protons in the atomic nucleus.
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Electrons are extremely
small compared to all of
the other parts of the
atom. The mass of an
electron is almost 1,000
times smaller than the
mass of a proton
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Electrons are found in clouds that surround
the nucleus of an atom. Those clouds are
specific distances away from the nucleus and
are generally organized into shells. Because
electrons move so quickly, it is impossible to
see where they are at a specific moment in
time.
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After years of experimentation, scientists
discovered specific areas where electrons are
likely to be found. The overall shape of the
shells changes depending on how many
electrons an element has. The higher the
atomic number, the more shells and electrons
an atom will have.
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The closer an electron is to the nucleus, the
greater the attractive force. Hence electrons
bound near the center of the atom require more
energy to escape than those at greater
separations.