Free Science Lessons: Group Seven Elements (Halogens)

Overview

• Objective: Understand the properties of Group Seven elements (halogens), focusing on molecular structure and changes in melting/boiling points.

Key Characteristics of Group Seven Elements

• Known as Halogens.
• Consist of non-metals.
• Have seven electrons in their outer energy level.
• Atoms react to achieve a full outer energy level.

Molecular Structure

• Group Seven elements form diatomic molecules.
  • Example: Fluorine (F₂) and Chlorine (Cl₂).
  • Atoms in these molecules share a pair of electrons, forming a covalent bond.
  • Represented as sticks between atoms in diagrams.

Melting and Boiling Points

• Melting and boiling points increase as you move down the group.
• Physical states at room temperature (approx. 20°C):
  • Fluorine and Chlorine: gases (boiling point < 20°C).
  • Bromine: liquid (melting point < 20°C, boiling point > 20°C).
  • Iodine: solid (both melting and boiling points > 20°C).

Relative Molecular Mass

• Indicates the size of the molecule.
• Increases down the group, meaning molecules become larger.
• Understanding relative molecular mass is crucial for further topics.

Additional Resources

• Refer to the vision workbook for practice questions.

Note: Further details on covalent bonding and relative molecular mass will be covered in later topics.