(40) GCSE Chemistry Revision "Group 7 Part 2 Compounds of the Halogens"

Introduction to Group Seven Elements

• Group Seven elements are also known as the halogens.

• Found on the right side of the periodic table; all are non-metals.

Valence Electrons

• Group Seven elements have seven electrons in their outer energy level.

• Examples:

  • Fluorine

  • Chlorine

Covalent Compounds Formation

• Group Seven elements form covalent compounds when reacting with other non-metals.

  • Covalent Bond: A pair of electrons shared between two atoms.

  • Example of covalent bond formation:

    • Fluorine Molecule (F2): Formed by two fluorine atoms sharing a pair of electrons.

• Example of a covalent compound formation:

  • Hydrogen Chloride (HCl): Formed when chlorine (non-metal) reacts with hydrogen (non-metal).

    • Both require one extra electron to achieve full outer energy levels.

  • Represented with a stick showing the covalent bond.

• Additional examples of covalent compounds formed:

  • Bromine + Carbon = Covalent compound

  • Iodine + Phosphorus = Covalent compound

Ionic Compounds Formation

• When halogens react with metals, they form ionic compounds.

  • Example reaction:

    • Chlorine (halogen) + Lithium (metal)

      • Lithium has 1 electron in its outer energy level.

      • Chlorine has 7 electrons in its outer energy level, needing one more to complete it.

• Electron Transfer:

  • Chlorine atom gains one electron from lithium.

  • Charged particles formed:

    • Chlorine: 17 protons (positive charge) + 18 electrons (negative charge) = -1 charge (chloride ion).

Halogen Ions

• Halogen ions formed consistently have a negative one charge.

• Naming convention:

  • Halogen name ends with "ide" for the ion.

    • Examples:

      • Fluorine -> Fluoride

      • Chlorine -> Chloride

Conclusion

• Understanding the covalent and ionic bonding behaviors of Group Seven elements is essential for study.

• Resources available for further questions in revision workbook.