Periodicity

• In the periodic table, how are elements arranged?

  Increasing atomic number
• A period is a horizontal row of elements in the periodic table
• Elements in a group have similar chemical properties because they have the same number of outer shell electrons.
• Periodicity is a repeating pattern of properties across different periods
• Match the block in the periodic table with its correct name:

  s-block ↔️ S

  p-block ↔️ s

  d-block ↔️ p

  f-block ↔️ f
• Arrange the following elements from Period 3 in order of increasing atomic number:

  1️⃣ Na

  2️⃣ Mg

  3️⃣ Al

  4️⃣ Si

  5️⃣ P

  6️⃣ S

  7️⃣ Cl

  8️⃣ Ar
• First ionization energy increases across the period with a dip between groups 2 and 3 and between groups 5 and 6
• What is the definition of first ionization energy?

  Energy to remove one mole of electrons
• Atomic radius decreases across a period.
• Positive ions are smaller than their atoms
• Negative ions are larger than their atoms
• What is electronegativity defined as?

  Ability to attract electrons
• Electronegativity increases across a period.
• Variations in melting and boiling points are due to changes in structure and bonding
• Arrange the following molecules in order of increasing melting point:

  1️⃣ Cl₂

  2️⃣ P₄

  3️⃣ S₈
• What type of bonding is present in argon?

  Weak van der Waals forces
• Atomic radius decreases across period 3 because the nuclear attraction to outer electrons is greater
• Arrange the following elements from Period 3 in order of increasing first ionization energy:

  1️⃣ Na

  2️⃣ Mg

  3️⃣ Al

  4️⃣ Si

  5️⃣ P

  6️⃣ S

  7️⃣ Cl

  8️⃣ Ar
• Silicon has a very high melting point because it is a giant covalent structure.