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Hydrogen (H) & helium (He) make up (basically) all of the Universe's mass (around 99%, leaving less than 1% for the remaining elements); after all, it's the nuclear fusion of H into He that powers the vast majority of stars illuminating the cosmos.  On Earth, however, hydrogen and helium are scarce: together, they account for far less than 1% of the planet’s mass [SB, 2013].  Even within the Earth’s crust (part of the lithosphere, 30–70 km thick), hydrogen and helium constitute only a tiny fraction compared to heavier elements, which were formed over successive generations of stars and, once abundant, allowed the formation of rocky planets [SB, 2013].

Figure 1 shows the abundance of elements in the universe & in Earth’s crust (thickness of about 100 km), while Figure 2 shows the chemical composition of the bulk Earth: iron is, by mass, the most common element on Earth, and the 6th most common element in the Earth's crust, being mainly deposited by meteorites in its metallic state, with its ores also being found there.  Figure 3 shows the chemical composition of the atmosphere (3/4 of its mass is within about 11 km).

Figure 1: Abundance of elements in the (a) universe & (b) Earth’s crust (in atom percent)