FSS - The Ingredients of a Planet Lesson

 

The Ingredients of a Planet

recipe for planet
elements
atoms
compounds and moleculesEvery substance found on Earth is made of atoms of at least one element.   Elements are substances that are composed of only one type of atom- gold, for example- and can sometimes be found on Earth in their pure form; gold (again), silver, and copper are all examples of pure elements that can be found on Earth.   Other elements, such as oxygen, are highly reactive and can therefore only be found combined with other atoms.  

An atom is the smallest unit of an element that retains all of the properties of that element.   Atoms are comprised of a nucleus, containing at least one proton and usually a quantity of neutrons, and electrons orbiting the nucleus.   The properties of an element are determined by the number of protons in the nucleus- all atoms with eight protons in their nucleus are oxygen atoms, all atoms with six protons are carbon atoms, etc.   The number of neutrons and electrons can vary; oxygen atoms can have different numbers of neutrons, and different numbers of electrons, but they all must have eight electrons.

Atoms that are chemically bonded together- either through ionic or covalent bonds- are known as molecules.   If the atoms bonded together represent more than one element, then the molecule is known as a compound.

All compounds are molecules, but not all molecules are compounds.   For example, water is a compound composed of hydrogen atoms covalently bonded to oxygen atoms; a molecule of water is two hydrogen atoms bonded to one oxygen atom (written as H2O).   Oxygen atoms can also combine with other oxygen atoms to make O2  (or even O3), but these combinations are not considered to be compounds (O2  is molecular oxygen, while O3  is ozone, but neither is a compound by definition).

There are around 90 naturally occurring elements found on Earth, and these elements bond together in various combinations to make every substance found on (or within) the Earth.  But what about the other planets in our solar system? What are they made of?

The explanations for how and why they bond together are beyond the scope of this course.   However, understanding how they make up the Earth itself is something that we'll need to investigate.   To get a better understanding of this, we need to look beyond chemistry.

 

 

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