1. Oxygen (O): Makes up about 46.6% of the crust by weight.
2. Silicon (Si): Makes up about 27.7% of the crust by weight.
3. Aluminum (Al): Makes up about 8.1% of the crust by weight.
4. Iron (Fe): Makes up about 5.0% of the crust by weight.
5. Calcium (Ca): Makes up about 3.6% of the crust by weight.
6. Sodium (Na): Makes up about 2.8% of the crust by weight.
7. Potassium (K): Makes up about 2.6% of the crust by weight.
8. Magnesium (Mg): Makes up about 2.1% of the crust by weight.
These eight elements make up over 98% of the Earth's crust by weight.
