Final answer:
Eleven elements make up about 99% of the Earth's crust, oceans, and atmosphere, with oxygen being the most abundant, followed by silicon. In contrast to the universe where hydrogen and helium are most common, Earth has a vastly different elemental makeup.
Step-by-step explanation:
Approximately 99% of the mass of the earth's crust, oceans, and atmosphere is made up by just eleven elements. These elements include oxygen, which alone makes up nearly half of this mass, while silicon accounts for roughly a quarter. The dominance of oxygen is visible as it constitutes about 46.1% of the earth's crust's mass, mostly found in chemical compounds with other elements. Together with oxygen, elements such as silicon, aluminium, iron, calcium, sodium, potassium, and magnesium round out the major components that form the bulk of the Earth's crust. Even though hydrogen is the most abundant element in the universe, it makes a minuscule portion of the Earth's crust at only 0.14%.
Interestingly, the presence and concentration of elements differ vastly when looking at the universe as a whole compared to Earth. For instance, hydrogen and helium dominate the cosmos but are not as prevalent in Earth's composition. Inside Earth's atmosphere, which has a total mass around 5 × 10¹⁸ kilograms, oxygen also plays a crucial role by forming about 20% of the atmosphere's mass and is essential for the oxygen cycle vital to life processes.