Unit 1: Elements and Compounds

Wilson School Online Science Book

Unit 1.1: Elements

What are Elements?

Ever wonder what makes the world the world? Stop wondering and start reading. Everything you can touch, taste, or smell is made of one or more elements working together to create that substance. Elements are the very building block of our world. They join together and create everything. Elements, often also called atoms, are microscopic and can not be seen by the naked human eye. In total, there are 118 elements in our world, all listed in the Periodic Table of Elements.

The Periodic Table of Elements

The Periodic table of Elements is a list of all the elements there is. Within this large table, there are three smaller groups called metalloids, metals, and non-metals. If you haven't noticed, each element it represented by a atomic letter and number, along with its atomic mass and full element name. For Example, H2O (water) is 2 hydrogen (H) atoms and 1 oxygen (O) atom.
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Metals, Non-Metals, and Metaloids


Some Characteristics of Metals include, but are not limited to:

  1. often conductive of electricity
  2. malleable
  3. shiny
  4. sometimes magnetic

These can be found on the left side of the Periodic Table of Elements.


Some Characteristics of Non-Metals include, but are not limited to:

  1. typically not conductive of electricity
  2. not malleable
  3. dull
  4. not magnetic

Basically, these have the opposite characteristics that Metals do. These are found on the right side of the Periodic Table of Elements above the staircase (will talk about later).


Characteristics of Metalloids are in-between Metals and Non-Metals. Some are and some aren't magnetic. These elements are located going diagonal on the Periodic Table of Elements, otherwise known as the staircase.

Question 1

List examples of metals, non-metals, or metalloids.


  1. ___________________________________
  2. ___________________________________
  3. ___________________________________
  4. ___________________________________
  5. ___________________________________

Question 2

Check all the true statements:

[] Only non-living things are made of elements

[] Only living things are made of elements

[] Elements are only in certain things

[] Everything is made of one of more elements

Unit 1.2: Compounds

What are Compounds?

There is only 118 elements, but surly there isn't only 118 things on earth. This is because elements can be combined to make compounds. Compounds are two or more elements that are chemically combined so that there atoms are connected. For example, table salt (NaCl) is a compound. It consist of 2 elements, sodium (Na) and chlorine (Cl). These elements have been chemically combined. Another example is water (H2O) which is 2 hydrogen (H) atoms and 1 oxygen atom (O)

Counting Compounds

In the example in the paragraph above, it is stated that table salt (NaCl) is only 2 elements. How can you tell? Every element is represented by one capital letter and in some cases, a second lowercase letter. By counting the number of capital letters there are in a formula, you can tell how many elements there are. Some formulas, like water (H2O), have numbers in them. These represent how many of that elements is present. In water (H2O), there is 2 hydrogen atoms (H) because there is a 2 behind the element. There is only 1 oxygen (O) atom because there is no number behind the element. When looking at most formulas, the number(s) will be small and towards the bottom of the formula.

Watch the Video

Atoms elements and compounds