The two most abundant elements in the Earths crust are__________

The two most abundant elements in the Earths crust are__________

• A. Aluminum and Iron
• B. Calcium and Magnesium
• C. Sodium and Potassium
• D. Silicon and O2

Answer: (D)

Oxygen and silicon are the two most abundant elements in Earth’s crust because most crust rocks are silicate minerals built from networks of silicon-oxygen units. Oxygen is the most plentiful element by mass in the crust, largely because it forms oxide parts of these minerals, and silicon provides the major structural framework with silicon-oxygen tetrahedra. Minerals like quartz and feldspars exemplify this pair, containing large amounts of both elements. The rest of the crust’s composition comes from aluminum, iron, calcium, magnesium, sodium, potassium, and a few others in much smaller amounts. So the crust’s bulk makeup is dominated by oxygen and silicon, which is why the correct choice lists silicon and O2.

Oxygen and silicon are the two most abundant elements in Earth’s crust because most crust rocks are silicate minerals built from networks of silicon-oxygen units. Oxygen is the most plentiful element by mass in the crust, largely because it forms oxide parts of these minerals, and silicon provides the major structural framework with silicon-oxygen tetrahedra. Minerals like quartz and feldspars exemplify this pair, containing large amounts of both elements. The rest of the crust’s composition comes from aluminum, iron, calcium, magnesium, sodium, potassium, and a few others in much smaller amounts. So the crust’s bulk makeup is dominated by oxygen and silicon, which is why the correct choice lists silicon and O2.