Study Notes
Periodic trends describe how elements change from metallic to non-metallic character across a period and how their properties can be predicted based on their position in the Periodic Table.
- Metallic Character — Elements change from metallic to non-metallic character from left to right across a period. Example: Metals are shiny, conductive, and malleable.
- Group Number — Indicates the number of electrons in the outer shell. Example: Group 1 elements have one valence electron.
- Alkali Metals — Group 1 elements that are very reactive and have low melting points. Example: React with water to produce hydrogen gas.
- Alkaline Earth Metals — Group 2 elements that are less reactive than alkali metals. Example: React with water to produce hydrogen gas.
- Halogens — Group 7 elements that are highly reactive non-metals. Example: Form diatomic molecules and react with metals to form ionic compounds.
- Noble Gases — Group 8 elements that are unreactive due to a full valence shell. Example: Used in lighting due to their spectral properties.
Exam Tips
Key Definitions to Remember
- Metallic character: Shiny, conductive, and malleable properties of metals.
- Group number: Indicates the number of valence electrons.
- Alkali metals: Highly reactive metals in Group 1.
- Noble gases: Unreactive gases in Group 8 with full valence shells.
Common Confusions
- Confusing the reactivity of alkali metals with alkaline earth metals.
- Misidentifying the position of non-metals in the Periodic Table.
Typical Exam Questions
- What happens to metallic character across a period? It decreases from left to right.
- How do you predict the properties of an element based on its position? By using its group and period number.
- Why are noble gases unreactive? They have a full valence shell of electrons.
What Examiners Usually Test
- Understanding of periodic trends such as metallic to non-metallic character.
- Ability to predict properties of elements based on their position in the Periodic Table.
- Knowledge of characteristic properties of different groups like alkali metals and noble gases.