Chemistry Lesson 2: Classification of Matter

Study Notes

Objectives:
- Compare and contrast pure substances and mixtures
- Differentiate between elements and compounds
Success Criteria:
- All students will differentiate between pure substances and mixtures
- Most students will differentiate between elements and compounds
- Some students will analyze changes in subatomic particles (e.g., adding or losing electrons)
Engage: Watch a video
- https://youtu.be/m7nOzfZEem8 (Video to compare pure substances and mixtures)

Substance: Matter that has a consistent composition. It has a fixed combination of atoms.
- Definiton: Matter with a composition that is always the same
- Examples: Elements and compounds
Element: A substance made of only one type of atom.
- Examples: Aluminum, Oxygen, Chlorine, Carbon
Compounds: A substance containing two or more different elements that are chemically bonded together.
- Examples: Water (H₂O), Sodium Chloride (NaCl), Methane (CH₄)
Types of Substances:
- Elements:
  - Consist of only one type of atom.
  - Examples in the presentation: Aluminum (Al), Oxygen (O), Chlorine (Cl), and Carbon (C) shown as images (along with other chemical symbols)
Elements on the Periodic Table:
- Most elements are considered metals. These are on the left side of the periodic table like Aluminium.
- Metalloids act as intermediate on the periodic table between metals and nonmetals like Boron.
- Nonmetals are on the right side like Oxygen.
Atoms of Elements:
- Atoms are the fundamental building blocks.
- Each element has a unique number of protons, which is reflected in its position on the periodic table.
- For example, aluminum has 13 protons while oxygen has 8.
- Atoms of the same element can exist in different forms (individually or in pairs), as seen in the examples of Aluminum(individually) and Oxygen(in pairs).

Definition: A substance that consists of just one type of atom, such as Aluminum, Oxygen, Chlorine, or Carbon.

Figure 3: Periodic table showing elements, with examples of Aluminum and Oxygen (and their protons and atomic mass).
- Elements contain one type of atom.
- Most elements are metals.
- Metals like aluminum are on the left side of the periodic table.
- Metalloids are between metals and nonmetals.
- Nonmetals are on the right side.
Figure 4: (Images of the arrangement of atoms)
- Some elements are made of more than one atom (e.g., Hydrogen H₂).
- Elements consist of one type of atom (e.g., Helium He)
- Compounds consist of two or more different types of atoms bonded together (e.g., Carbon Dioxide CO₂).

Differentiate elements from compounds:
- Elements: Consist of one type of atom
- Compounds: Consist of two or more types of atoms chemically combined

An activity game is provided to help students evaluate and identify elements and compounds.
- https://wordwall.net/resource/23669223/atoms-elements-and-compounds-match-up for a matching activity.