C3 1.1 - The Early Periodic Table.
- The periodic table of the elements, developed as an attempt to classify the elements. It arranges them in a pattern according to their properties.
- Early versions of the periodic table failed to take account of the fact that not all of the elements were known at that time.
- Mendeleev's table took account of unknown elements, and so provided the basis for the modern periodic table.
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C3 1.2 - The Modern Periodic Table.
- The group that an element is in is determined by its atomic (proton) number.
- The number of electrons in the highest energy level of an atom, determines its chemical properties.
- We can explain trends as we go down a group, in terms of the number of energy levels in the atoms.
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C3 1.3 - Group 1 - The Alkali Metals.
- The elements in Group 1 of the periodic table are called the alkali metals.
- The metals all react with water to produce hydrogen and an alkaline solution containing the metal hydroxide.
- The reactivity of the alkali metals increases as we go down the group.
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C3 1.4 - Group 7 - The Halogens.
- The halogens exist as diatomic molecules.
- The halogens all form ions with a single, negative charge.
- The halogens fom covalent compounds by sharing electrons with other non-metals.
- The reactivity of the halogens decreases going down the group.
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C3 1.5 - The Transition Elements.
- Nearly all the transition elements have high melting points, and high densities.
- The transition metals are strong and hard, and are good conductors of electricity and heat.
- The transition metals do not react vigorously with oxygen or water.
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