Y8 - C4 The Periodic Table

• ​KNOW IT - Know the key words and definitions for this topic

• ​THINK IT - Describe how the modern periodic table was developed

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• GRASP IT - Explain the ​trends in reactivity for Group 1 and 7.

• ​Atoms - The smallest particle (i.e an Oxygen atom)

• ​Elements - A substance made from only one type of atom

• ​Molecule - Two or more atoms bonded together (i.e O₂)

• ​Compounds - Two or more atoms of different types bonded together (ie H₂O)

​Dalton - Ordered elements by atomic mass, used symbols.

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​Newlands - Ordered elements by atomic mass, Discovered that every 8th element was similar so he put the elements in 8 groups (law of octaves). But he ended up with some of the elements in groups with elements with different properties.

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​Mendeleev - Ordered elements by atomic mass. Kept the 8 groups but swapped some elements around so they are in the correct groups. Left gaps for undiscovered elements and predicted their properties

• ​Physical

  • ​Density

  • ​Boiling / Melting point

  • ​Appearance

  • ​Solubility​

• ​Chemical

  • ​Reactivity

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• ​React with water to make an alkali and hydrogen gas

• ​Have 1 electron in the outer, therefore want to LOSE 1 electron.

• ​Down the group the atoms get bigger, so the nuclear pull is less

• ​Down the group there is MORE shielding, so the nuclear pull is less

• ​Therefore down the group it is EASIER to LOSE the electron

• ​Have 7 electron in the outer, therefore want to GAIN 1 electron.

• ​Down the group the atoms get bigger, so the nuclear pull is less

• ​Down the group there is MORE shielding, so the nuclear pull is less

• ​Therefore down the group it is HARDER to GAIN the electron