Acids and Bases_1

Acids and Bases_1

1. Atomic Structure:

   • An atom is made up of three parts:
     • Proton - positive charge
     • Neutron - neutral or no charge
     • Electron - negative charge
   • - atomic number
   • atomic mass
   • bottom number - top number = number of neutrons. number of protons = number of electrons

2. Nucleus:

   • This is the centre of the atom.
     • It is made up of protons and neutrons.

3. Electrons

   • These are found orbiting the nucleus.
   • They are arranged in shells.
   • The first shell can hold a maximum of 2 electrons.
   • Outer shells can hold a maximum of 8 electrons.

4. Isotopes:

   • Are atoms that have the same atomic number, but a different atomic mass.
     • This is because they still have the same number of protons (and therefore electrons) but a different number of neutrons.
       • E.g Carbon isotopes:
         • - same atomic number
           • - but different atomic mass

5. Atomic number = number of protons ( = number of electrons).

6. Atomic mass - number of protons + number of electrons.

7. Number of neutrons = atomic mass - atomic number.

8. Ions:

   • The atomic numbers = number of protons. This determines what element you are.
     • Isotopes are the same element with different numbers of neutrons.
       • Ions are the same element with different amounts of electrons.
   • When an atom gains or loses electrons, it becomes an ion. Ions form because atoms "want" to gain a full outer shell of electrons. They do this by gaining or losing electrons.
     • If an atom gains an electron, there will be more nagative charges than positive, so the atom will now be negatively charged. ANION.
       • ANION because the bottom of AN IRON has minuses on it.
     • If an atom loses an electron, there will be more positive charges than negative, so the atom will now be positively charged. CATION.
       • CATION because we're always positive about cats.

9. Ionic Bonding:

   • Ionic bonding involves the transfer of an electron (or more) from one atom (which becomes positively charged - CATION) to another atom (which becomes negatively charged - ANION).
     • Together they will form a neutral compound.
   • Generally, ionic bonds form between metals (CATIONS) and nonmetals (ANIONS)
     • - (the positive of Na is cancelled out by the negative of Cl).

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