Question

Consider the following statements regarding the composition of the Earth's crust:

1. I. Approximately 98% of the crust is composed of eight major elements.
2. II. Silicon is the second most abundant element, contributing more than a quarter of the crust's weight.
3. III. Elements like Titanium and Hydrogen are part of the 'Major Rock-forming Minerals' group.

• A. ii only
• B. None of these
• C. i, ii
• D. All

Answer 1

Answer:

C. i, ii

Composition of Earth's Crust

• The Earth's crust, the outermost solid shell, is primarily composed of eight major elements which collectively account for approximately 98% of its total mass.
• Oxygen is the most abundant element, making up about 46.6% of the crust's weight.
• Silicon is the second most abundant element, constituting roughly 27.7% of the crust's weight.
• Following oxygen and silicon, other significant elements include aluminum (8.1%), iron (5.0%), calcium (3.6%), sodium (2.8%), potassium (2.6%), and magnesium (2.1%).
• The vast majority of the Earth's crust is made up of silicate minerals, which are compounds of silicon and oxygen.
• Elements like Titanium and Hydrogen are not considered among the eight major elements and are not typically classified within the 'Major Rock-forming Minerals' group in the same category as silicon and oxygen-based minerals.
• Major rock-forming minerals include feldspar, quartz, mica, pyroxene, amphibole, and olivine, which are predominantly composed of silicon and oxygen, along with other metallic elements.