Chemistry - 4th Form

Chemistry - 4th Form

1. Moles and Formula

2. Bonding

3. Kinetics

4. Atomic Structure

   • Key Terms
   • The Periodic Table
     • Classification of Elements
       • In general, the metals are on the left side of the periodic table, while the nonmetals are on the right. Elements are also organised into columns. Elements that are in the same column have the same number of electrons in their outer shell.
       • Non-Metals
         • Non-metals are generally poor thermal and electrical conductors, brittle, dull, and gain electrons easily.
       • Metals
         • Metals are generally shiny, are good conductors of electricity, have a high density and have high melting and boiling points.
     • Group 1 - The Alkali Metals
       • The alkali metals are soft, reactive metals. They react vigorously with water, and must be stored in oil in order to prevent contact with the air or water. They become more reactive as they go down, and all have 1 electron in their outer shell.  
       • Reactions
         • The alkali metals react with water to create a metal hydroxide(which is always aqueous) and hydrogen. In this reaction, lithium floats and fizzed steadily, sodium fizzes rapidly and sometimes burns with an orange flame, and potassium fizzes vigorously and is set on fire, creating a lilac flame. Reactivity increases when going down the group as the outer electron gets further away from the nucleus, meaning that there is less electrostatic force holding it in place. This means that it is easily lost to another element.
     • Group 7 - The Halogens
   • Structure of an Atom
     • Protons
       • -Grouped with neutrons in the nucleus of an atom -The number of protons is the same as the number of electrons  in an element, and is the same as the atomic number -Mass = 1 -Charge = +1
     • Neutrons
       • -Found in the nucleus of an atom, with the protons              -Weight = 1 -Charge = 0 -The number of neutrons can be calculated by subtracting the atomic number (the number of protons) from the relative atomic mass (the number of protons added to the number of neutrons).
     • Electrons
       • -Weight = 0 (9.1x10^-31kg) -Charge = -1  -In an element, the number of electrons is the same as the number of protons -Electrons can be gained or lost when elements bond and form compounds - Orbit the nucleus of an atom in shells (structure is 2,8,8)
   • Isotopes
     • Isotopes are atoms of an element with the same number of protons and electrons, but a different number of neutrons, meaning that they have a different RAM. Isotopes have the same chemical properties as the regular atom, but some can be radioactive.