Group 2

• State what is meant by the First Ionisation Enthalpy

  The First Ionisation Enthalpy of an element is the energy needed to remove one electron from every atom in one mole of isolated gaseous atoms of the element.
• What element is the least reactive in group 2 and won't react with steam , water or red heat?

  Beryllium
• Do elements in group 2 become more reactive or less reactive as you go down the group?

  As you go down the group, elements become more reactive.
• What do group 2 metals and water form?


  Forms metal hydroxide and hydrogen.
• What occurs as Group 2 is descended?

  The hydration enthalpies of the Group 2 cations become less negative
• For the elements in group 2, explain the similarities and trends in the way the elements react, in terms of their electronic configuration?

  1. Reactivity depends on electrons lost from the outer shell
  2. Going down the group as outer electrons are further from the nucleus
  3. So electrons are lost more easily
  4. Getting more reactive down the group
• What is charge density?


  Charge density is a measure of the concentration of charge on the cation.
• Does the group 2 carbonates solubility's increase or decrease as you go down the group?

  The group 2 carbonates become less soluble as you go down the group.
• What is ionisation energy measured in?

  Gaseous state
• How many electrons are removed during ionisation?

  1 electron at a time
• From where is the electron removed in a mole of atoms?

  From each atom in a mole
• What is required for ionisation to occur?

  Energy is required
• Why do subsequent ionisations require more energy?

  Less electrons increase attraction to nucleus
• What happens to shielding as electrons are removed?

  Less shielding occurs with fewer electrons
• What is the first ionisation energy reaction equation?

  X(g) -> X+(g) + e-
• What is the second ionisation energy reaction equation?

  X+(g) -> X2+(g) + e-
• What happens to the proton:electron ratio with successive ionisations?

  It increases with each ionisation
• Why do inner shell electrons experience greater attraction?

  Shorter distance to nucleus and less shielding
• What causes big jumps in ionisation energy?

  Removing an electron from a new shell
• How can the number of electrons before a big jump be determined?

  It indicates the outermost shell's electrons
• What is periodicity in the periodic table?

  • Regular repeating patterns in properties
  • Includes chemical and physical properties
• What do groups in the periodic table show?

  Elements with similar properties
• What do periods in the periodic table indicate?

  A trend in properties
• What is the definition of first ionisation energy?

  Energy to remove one electron from a mole
• What factors affect first ionisation energy?

  Nuclear charge, atomic radius, shielding
• How does nuclear charge affect ionisation energy?

  More protons increase attraction to nucleus
• How does atomic radius influence ionisation energy?

  Closer electrons require more energy to remove
• What is the effect of shielding on ionisation energy?

  More shells weaken attraction, less energy needed
• What is the trend of first ionisation energy down a group?

  It decreases down the group
• Why does first ionisation energy decrease down a group?

  Increased atomic radius and shielding outweigh nuclear charge
• What is the trend of first ionisation energy across a period?

  It increases left to right
• Why does first ionisation energy increase across a period?

  Increased nuclear charge with constant shielding
• What is the exception to the trend in ionisation energy for boron?

  Removing an electron from a higher sublevel
• Why does oxygen have a dip in ionisation energy?

  First paired electron experiences more repulsion
• What is the trend in melting points of period 3 elements?

  Melting points increase across the period
• Why do the first three period 3 elements have high melting points?

  Strong forces between metal ions and electrons
• What happens to melting points at silicon?

  Rapid increase due to giant covalent structure
• Why do remaining four elements in period 3 have lower melting points?

  Weak intermolecular forces require less energy
• How does the number of electrons affect melting points down the group?

  Fewer electrons weaken van der Waals forces
• What is the trend in melting points of period 2 elements?

  • Similar trend to period 3
  • Metals have high melting points
  • Non-metals have lower melting points