progress test revision

• oxidation


  loss of electrons
• reduction


  gain of electrons
• oxidation (O.S.)


  increase in oxidation state
• reduction (O.S.)


  decrease in oxidation state
• oxidising agent 


  species that accepts electrons
• reducing agent 


  species that donates electrons
• period


  horizontal row of elements with changing properties
• group


  vertical column of elements with similar chemical properties
• periodicity


  a repeating pattern in physical and chemical properties
• first ionisation energy across a period

  first ionisation energy increases across the period with a decrease between group 2 and 3 and between group 5 and 6

  explanation:

  more protons in nucleus

  e- added to same shell so similar shielding

  stronger attraction between nucleus and outer e-
• first ionisation energy


  the energy needed to remove one mole of electrons from one mole of atoms in the gaseous state
• trends in atomic radius across a period

  atomic radius decreases across the period

  explanation:

  more protons in nucleus

  e- added to same shell so similar shielding

  stronger attraction between nucleus and outer e-
• trends in ionic radius across a period

  positive ions are smaller than their atoms

  explanation:

  same number of protons attracting fewer e- so stronger attraction

  negative ions are bigger than their atoms

  explanation:

  same number of protons attracting more electrons so weaker attraction
• electronegativity 


  the power of an atom to attract the pair of electrons in a covalent bond
• trends in electronegativity across a period

  electronegativity increases across a period

  explanation:

  more protons in the nucleus

  electrons added to same shell so there is similar shielding

  stronger attraction between nucleus and bonding pair of electrons
• melting and boiling point Na to Al

  structure: giant metallic lattice

  bonding: stronger attraction between positive metal ions and delocalised electrons

  Na to Al mpt/bpt increases as greater charge on positive ion with more delocalised electrons so stronger attraction between positive ions and delocalised electrons