Unit A: Chemical Change

Lesson 1.1: The Structure of Matter (Part 1)

Have you watched the Tour de France or the speed skating events at the Olympics? Did you know that the materials used to make the bicycles, skates, helmets, and clothing are very important to an athlete’s success? These materials need to be strong and lightweight. Scientists need to know the elements needed to make these special materials.

Although much of this lesson is review, it should be thoroughly completed as most of the concepts for this unit build upon this knowledge.

  1. Define element
  2. Recall the parts of an atom, including electrons, protons, neutrons and the nucleus.
  3. Describe an atom using atomic number, atomic mass and mass number
  4. Compare electron, protons and neutrons by location, mass and charge.
  5. Make Bohr diagrams for the first 18 elements on the periodic table.
  6. Make Lewis Dot diagrams for the the first 18 elements on the periodic table.
  7. Define valence electrons
  8. Compare Alkali Metals, Halogens and Noble Gases in terms of valence electrons
  9. Give the similarity of structure and properties in a group (family) on the periodic table
  10. Differentiate between an atom and an ion

Recall the structure of an atom.  Read pages 6 - 7.  

Do questions 1 - 3 on page 8.  Check your answers below. 

Courtesy of Alberta Education

 
Two types of diagrams are useful to help us understand the structure of atoms and ions.  Bohr diagrams help us see how many energy levels electrons occupy, and help us to predict the charge on an ions.  Lewis diagrams show us the valence electrons which help us understand the shape of molecules and predict chemical reactivity.  It is very useful to know how to construct these two kinds of diagrams.

Read pages 8 - 9.  Do part 2 of the Element Builder Gizmo activity.  You may want to view the videos below. 


Recap:  When making Bohr diagrams the first three energy levels are full with 2, 8 and 8 electrons.If the outermost energy level is full, it is an atom.  If the outermost energy level is not full, it is an ion.  The outermost electrons are called valence electrons.

Lewis Dot diagrams show only valence electrons.   Single electrons are added first, then pairs are formed.

Do questions 5 and 6, and check your answers below.

Science 20 Textbook, Courtesy of Alberta Education


This activity helps you relate the structures (diagrams) of atoms to their properties and location on the periodic table.  You should become familiar with the Alakli Metal, Halogen and Noble Gas groups.

Check you answers below.

Science 20 Textbook, Courtesy of Alberta Education