Atomic Theory and The Periodic Table Page:
The Periodic Table and Subatomic Particles:
Atoms readily gain or lose electrons during chemical reactions. The charged particle formed when electrons are added to or removed from an atom is called an ion.
- The atomic number is equal to the number of protons.
atomic number = # electrons
- In a normal atom # of protons = # of electrons, making the number of positively charged particles and the number of negatively charged particles equal.
- The mass number is equal to the total of the protons and neutrons.
neutrons = mass # - atomic #
- Since an atom does not have fractions of neutrons, in this class we will round off the mass number to the nearest whole number.
- Protons and neutrons are made up of even smaller particles called quarks.
The chemical properties of ions are very different from the chemical properties of the atoms from which they form.
Ions with a positive charge, (electrons removed),
are called cations.
Ions with a negative charge, (electrons added),
are called anions.
Element Ball Project