Unit 1 Chemistry Test Revision.

Unit 1 Chemistry Test Revision.

1. There are three subatomic particles in the atom and each has a different mass and charge.

   • PROTONS - These are situated in the nucleus of the atom. They have a +1 mass and positive charge.
   • ELECTRONS - These are situated in the shells of the atom. they have a 1/1837 mass and a negative charge.
   • NEUTRONS - These are situated in the nucleus of the atom. They have a +1 mass and no chrge.

2. The nucleus has no overall charge because the protons that have a positive charge and the electrons that a negative charge equals to each other.

   • ATOMIC NUMBER - the number of protons in an atom.
   • MASS NUMBER- The number of protons AND neutrons in an atom.

3. Isotopes are element atoms that have the same atomic number but different mass number.

   • RELATIVE ATOMIC MASS = (isotope 1 x mass 1) + (isotope 2 x mass 2)/100
   • Ion is a charged atom. Cation is a positive atom and Anion is a negative ion.