Curriculum
Science — First Preparatory
Unit 1: Matter
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Unit 2: Forces
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Unit 3: Life
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Unit 4: Earth and Space
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Text lesson
The Periodic Table
The Periodic Table
Important groups
Important groups
| Group | Name | Examples | Distinctive property |
|---|---|---|---|
| 1 | Alkali metals | Lithium, sodium, potassium | Very reactive; react vigorously with water |
| 17 | Halogens | Fluorine, chlorine, bromine, iodine | Very reactive; form salts with metals |
| 18 | Noble gases | Helium, neon, argon |
|
- Across a period, metallic character decreases and non-metallic character increases as we move from left to right.
- Helium is placed in group 18 even though it has only 2 electrons, because its only level is full.
The Periodic Table · 3 / 6