Cloud Model

Atoms consist of the following subatomic particles:

Protons have a positive charge (p+)

Neutrons have no charge; that is, they are neutral (no)

Electrons have a negative charge (e-)

The protons and neutrons are found in the nucleus (in the center of the atom).

The number of negatively-charged electrons equals the number of positively-charged protons so that overall, an atom is electrically neutral.

In the cloud model of an atom, electrons spin around the nucleus(like bees swarming around a nest).

Helium atom QM


Later, you’ll learn about the Bohr model of atoms (shown below). Although we know that electrons are actually spinning around the nucleus as described by the cloud model, the Bohr model will be helpful in understanding how atoms interact with each other during a chemical reaction.



What are the names of the particles in an atom and what kind of charge do they have?

What is the name of the part of the atom in the center and what particle(s) are in it?
The nucleus contains protons and neutrons.

How does the number of electrons compare to the number of protons in an atom?
They are equal in number so that an atom is electrically neutral.

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