Periodicity

• Who is the presenter of the periodicity video?

  Chris Harris
• What is the purpose of the periodicity video?

  To provide an overview of periodicity
• What specification is the video targeted at?

  AQA specification
• How are elements arranged in the periodic table?

  By proton number, not mass number
• What do groups in the periodic table represent?

  Columns of elements
• How many electrons do group one elements have in their outer shell?

  One electron
• What happens to the reactivity of group one elements with water?

  They react violently, increasing down the group
• What do periods in the periodic table represent?

  Rows of elements
• How many electron shells do elements in the same period have?

  The same number of electron shells
• What are s-block elements characterized by?

  Electrons in the S orbital
• What happens to atomic radius across period 3?

  It decreases
• Why does atomic radius decrease across a period?

  Increased nuclear charge pulls electrons closer
• What is the effect of shielding on atomic radius?

  It protects inner electrons from the nucleus
• What happens to atomic radius down a group?

  It increases
• Why does atomic radius increase down a group?

  Extra electron shells are added
• Why does magnesium have a higher melting point than sodium?

  Magnesium has a higher positive charge
• What type of structure does silicon have?

  Giant covalent structure
• What determines the melting point of phosphorus?

  Van der Waals forces
• Why does sulfur have a higher melting point than phosphorus?

  It has larger van der Waals forces
• What is the trend in melting points for metals in period 3?

  They generally increase
• What is ionization energy?

  Energy to remove one mole of electrons
• What is the melting point of chlorine compared to sulfur?

  Lower than sulfur
• What is the state of argon at room temperature?

  Monoatomic gas
• What is the first ionization energy of sodium?

  +495.8 kJ/mol
• What is the effect of shielding on ionization energy?

  More shielding means less energy required
• How does atomic size affect ionization energy?

  Bigger atoms require less energy to ionize
• What happens to ionization energy as we go down a group?

  It decreases
• Why does ionization energy decrease down a group?

  Outer electrons are further from the nucleus
• What is the trend in ionization energy across a period?

  It increases
• Why does ionization energy increase across a period?

  More protons increase nuclear attraction
• What is the significance of the exceptions in ionization energy trends?

  They indicate subshell structure and electron repulsion
• How does the outer electron configuration of aluminum affect its ionization energy?

  It is shielded and requires less energy
• What causes the drop in ionization energy for sulfur compared to phosphorus?

  Electron repulsion in the same orbital
• What are the key concepts related to periodicity that students should focus on for exams?

  • Shielding
  • Nuclear charge
  • Atomic radius
  • Trends in ionization energy
• What are the types of bonding and structures discussed in relation to melting points?

  • Metallic bonding in sodium, magnesium, aluminum
  • Giant covalent structure in silicon
  • Simple molecular structure in phosphorus and sulfur
  • Van der Waals forces in chlorine and argon
• What are the trends in melting points for elements in period 3?

  • Sodium, magnesium, aluminum: increase due to metallic bonding
  • Silicon: high melting point due to giant covalent structure
  • Phosphorus: lower melting point due to simple molecular structure
  • Sulfur: higher than phosphorus due to larger molecules
  • Chlorine: lower than sulfur due to smaller size
  • Argon: lowest, monoatomic gas
• What are the factors affecting ionization energy?

  • Atomic size
  • Shielding effect
  • Nuclear charge
  • Electron configuration
• What are the exceptions in ionization energy trends across periods?

  • Aluminum: lower ionization energy due to subshell shielding
  • Sulfur: lower ionization energy due to electron repulsion