Which of the following pairs of minerals form the bulk of the inner core of the earth

Step 1: Analyze the question The question asks which two minerals (elements) make up most of the earth's inner core, the innermost layer.

Step 2: Explain the concept The earth has these main layers:

• Crust: the outer layer, rich in silicon and aluminum (the continental crust is called SIAL).
• Mantle: rich in silicates of magnesium and iron (SIMA is the oceanic crust and upper mantle).
• Outer core: liquid, mostly iron and nickel.
• Inner core: solid, mostly iron and nickel, under enormous pressure.

The inner core and the outer core together are sometimes called NIFE, from Ni (nickel) and Fe (iron).

Step 3: Check the options

• A. Aluminum and iron: aluminum is concentrated in the crust, not the core. ✗
• B. Iron and nickel: these are the main constituents of the core (NIFE). ✓
• C. Tin and columbite: these are economic minerals found in Nigeria (for example on the Jos Plateau). They are not core materials. ✗
• D. Silicon and copper: silicon is abundant in the crust and mantle, and copper is only a minor element. ✗

Step 4: Answer The inner core is made mainly of iron and nickel, which is option B.

Exam tip: Remember NIFE for the core, SIMA for the oceanic crust and upper mantle, and SIAL for the continental crust. If a question mentions the core, think "Ni + Fe."