What are the 2 elements that make up Earth's core?
The Earth's core is mainly made of iron and nickel.
The solid inner core is made of mainly iron crystals with small amounts of nickel and heavier elements such as gold and platinum.
The liquid outer core is a nickel iron alloy with small amounts of heavier elements.
The presence of heavier elements has been deduced from the fact that the core's density is heavier than that of iron or iron/nickel alone.