Questions and Answers
What are Group 7 elements also called?
What are the physical states of halogens at room temperature?
Chlorine is a gas, bromine is a liquid, iodine is a solid.
Which halogen is pale green in color?
Chlorine
The melting and boiling points of halogens increase as you go down the group.
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Which halogen is found at the top of Group 7 and has the lowest melting and boiling points?
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What happens to the colors of halogens as you go down the group?
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What is the trend in reactivity for Group 7 non-metals?
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What occurs in a displacement reaction involving halogens?
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At room temperature, bromine is a ______.
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What is the electronic configuration of elements in Group 7?
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Study Notes
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.
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Description
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.
