Group 7 Elements Flashcards

Group 7 Overview

• Group 7 elements are called halogens, comprising non-metals including Fluorine, Chlorine, Bromine, Iodine, and Astatine.
• Halogens exist as diatomic molecules, meaning they consist of two atoms.

Physical States & Properties

• At room temperature (20 °C), physical states of halogens vary:
  • Chlorine is a gas
  • Bromine is a liquid
  • Iodine is a solid
• Halogens display a trend in color:
  • Fluorine is pale green
  • Bromine is red-brown
  • Iodine is black.

Melting and Boiling Points

• The melting and boiling points of halogens increase down the group.
• Fluorine at the top has the lowest melting and boiling points.
• Astatine at the bottom has the highest melting and boiling points.

Reactivity Trends

• Reactivity of halogens increases as you move up the group.
• Chlorine is the most reactive, while Iodine is the least reactive among Chlorine, Bromine, and Iodine.

Displacement Reactions

• More reactive halogens displace less reactive halogens in aqueous solutions of their halides.
• Example: Chlorine displaces bromine from potassium bromide solution, forming potassium chloride.

Aqueous Solutions

• When chlorine is added to a colorless potassium bromide solution, it turns orange due to bromine formation.
• Reaction:
  • ( \text{Cl}_2 (aq) + 2 \text{KBr} (aq) \rightarrow 2 \text{KCl} (aq) + \text{Br}_2 (aq) )

Halogen vs. Halide Displacement

• Bromine can displace iodine from an aqueous solution of magnesium iodide.
• Reaction:
  • ( \text{Br}_2 (l) + 2 \text{MgI} (aq) \rightarrow 2 \text{MgBr} (aq) + \text{I}_2 (aq/s) )

Electronic Configuration

• Halogens have seven electrons in their outer shell, requiring one more electron to achieve a full outer shell.
• As you ascend Group 7, the number of electron shells decreases, enhancing the attraction of the nucleus for the outer electrons, thus increasing reactivity.

Summary of Trends

• Physical properties (melting/boiling points, states, and colors) show distinct trends down the group.
• Reactivity trends reveal that halogens become more reactive as one moves up the group.

Test your knowledge of Group 7 elements, also known as halogens, with these flashcards. Learn about their physical states, properties, and characteristics. This quiz covers essential facts about halogens including their colors and trends in physical properties.