The Periodic Table

• How is the modern Periodic Table ordered?

  By atomic number
• How were the early lists of elements ordered?

  By atomic mass
• Why did Mendeleev swap the order of some elements?

  To group them by their chemical properties
• Why did Mendeleev leave gaps in his Periodic Table?

  Leave room for elements that had not yet been discovered
• Why do elements in a group have similar chemical properties?

  Have the same number of electrons in their outer shell
• Where are metals and non-metals located on the Periodic Table?

  Metals to the left, non-metals to the right
• What name is given to the Group 1 elements?

  Alkali metals
• Why are Alkali metals named this

  They are metals that react with water to form an Alkali
• Give the general equations for the reactions of Alkali metals with oxygen, chlorine, and water

  Metal + Oxygen - - - > Metal Oxide

  Metal + Chlorine - - - > Metal Chloride

  Metal + Water - - - > Metal Hydroxide + Hydrogen
• How does the reactivity of the Alkali metals change down the group?

  Increases (more reactive)
• Why does the reactivity of the Alkali metals increase down the group?

  They are larger atoms, so the outermost electron is further from the nucleus, meaning there are weaker electrostatic forces of attraction and more shielding between the nucleus and outer electron, and it is easier to lose the electron
• What name is given to the Group 7 elements

  Halogens
• Give the formulae of the first four Halogens

  F2 Cl2 Br2 I2
• How do the melting point of the Halogens change down the group?

  Increase (higher melting point)
• How does the reactivity of the Halogens change down the group?

  Decrease (less reactive)
• Why does the reactivity of the Halogens decrease down the group?

  They are larger atoms, so the outermost shell is further from the nucleus, meaning there are weaker electrostatic forces of attraction and more shielding between the nucleus and outer shell, and it is harder to gain an electron
• What is a displacement reaction?  

  When a more reactive element takes the place of a less reactive one in a compound
• What name is given to the Group 0 elements?

  Noble gases
• Why are noble gases inert?

  They have full outer shells so do not need to lose or gain electrons
• How do the melting point of the noble gases change down the group?

  Increase (higher melting point)