Elements & Compounds | Science

May 11, 2016 Jennifer Brandt

Elements & Compounds | Science 

As you study the physical science topics of the TASC Test Assessing Secondary Completion™ – specifically matter and its interactions – it’s important you understand what elements and compounds are. Today we will discuss these terms in-depth to give you a clear representation of each substance.

What is an element? 

According to Frostburg State University’s Department of Chemistry, an element is a type of matter that is composed of atoms with the exact same charge on their nuclei; that is, all atoms that make up an element have the same atomic number.

  • An atomic number is the number of protons in the nucleus of an atom. This number determines the chemical properties of an element and its place on the periodic table.

What is a compound?

According to Chemicool.com, a compound is a chemical substance that is formed when two or more elements are chemically bonded together.

These chemical bonds can either be covalent or ionic.

  • Covalent bonds are formed when one or more electron pairs between two atoms are shared.  
  • Ionic bonds are formed when one or more electrons from an atom or a group of atoms are transferred to another atom.

Elements & Compounds: A Side-by-Side Comparison

Use the following table to distinguish between elements and compounds:

Information via Diffen.com.




What makes it different?

Elements are distinguished by their atomic number.

Compounds are composed of different elements in a fixed ratio through chemical bonds.

Can it breakdown?


Compounds can breakdown into simpler substances when they undergo a chemical reaction.

How many are there?

There are around 117 elements.

There are millions of different chemical compounds.

What is it represented by?  

A symbol. Example: Copper is represented by the symbol Cu.

A formula. Example: Sodium Nitrate is represented by the formula NaNO3.


Iron, aluminum, zinc, copper, silver, gold, nickel, etc.

Water (H2O), Sodium chloride (NaCl), Sodium bicarbonate (NaHCO3), etc.


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