Rocks in the inner core of the Earth are rich in

Step 1: Analyze the question The question asks which materials are most abundant in the Earth's inner core, the innermost layer of the Earth.

Step 2: Explain the concept The Earth has three main layers:

• Crust (outermost): rich in silica and aluminium (sial) and silica and magnesium (sima)
• Mantle (middle): rich in silicates of iron and magnesium
• Core (innermost): divided into a liquid outer core and a solid inner core

The core is often called the NiFe layer (from the chemical symbols Ni for nickel and Fe for iron) because it is made mostly of nickel and iron. The inner core is solid because of the immense pressure, even though the temperature is extremely high (about 5,000°C or more).

Step 3: Check each option

• A. iron and nickel: Correct. This matches the NiFe composition of the core.
• B. nickel and magnesium: Magnesium is more characteristic of the mantle and the sima layer, not the core.
• C. lead and iron: Lead is not a major component of the core.
• D. nickel and lead: Lead is not a major component of the core.

Step 4: Answer

Exam tip: Remember the layers with this pattern:

• Crust = Sial / Sima (silicon-based)
• Mantle = silicates of Mg and Fe
• Core = NiFe (Nickel and Iron)

Whenever you see "core" in an exam, think "NiFe."