Question

What are the two most abundant elements by mass in the earth’s crust, oceans, and atmosphere? Does this make sense? Why? What are the four most abundant elements by mass in the human body? Does this make sense? Why?

Short answer

Oxygen and silicon are the two most abundant elements in the Earth's crust.

The four most abundant elements by mass in the human body are hydrogen, carbon, nitrogen, and oxygen.

Step-by-step solution

Define Elements

An element is a pure material made up completely of atoms with the same number of protons in their nuclei.

Explanation of the above question

The abundance of the chemical elements is the measure of the occurrence of the chemical elements in relation to all other environmental elements.

Oxygen and silicon are said to be the two most abundant elements in the Earth's crust.

The most abundant element in the atmosphere is said to be nitrogen.

Nitrogen gas (${\mathrm{N}}_2$) makes up about 78% of the air. Oxygen is said to be the second most abundant element in the atmosphere, and oxygen gas (${\mathrm{O}}_2$) makes up about 21% of the air.

The most abundant elements in the ocean by the proportion of mass in percentage are oxygen (85%) and hydrogen (10%).

By mass, human cells contain about 65-90% water (${\mathrm{H}}_2\mathrm{O}$), and a specific portion of the remainder is composed of carbon-containing organic molecules. Oxygen is then said to be contributing a majority of a human body's mass, followed by carbon. Almost 99% of the mass of the human body is made up of the following elements: hydrogen (H), carbon (C), nitrogen (N), and oxygen (O).

Therefore, the elements are Oxygen, silicon, hydrogen, nitrogen, and carbon.