Lesson 1.2: Atomic Bonding and Properties
Completion requirements
Unit A: Chemical Change
Lesson 1.2: Atomic Bonding and Properties
Did you know that aluminium, salt, and plastic are used in the manufacturing processes of music CDs? These are similar to the substances you observed and described in the “Observing Properties” activity at the beginning of this chapter. These three substances represent three categories of matter: metallic elements, ionic compounds, and molecular compounds.The focus of this unit is solutions. Solutions form when ionic compounds or groups of molecules are pulled apart by breaking their bonds. This section reviews and explores the basic ideas concerning bonding in ionic and molecular compounds to prepare for Section 1.3. Be sure to look at the targets for this section.
1. Locate metals and non-metals on the periodic table
2. Identify the properties of metals and non-metals (conductivity, luster and malleability [does it bend or break})
3. Define compound.
4. Describe ionic and covalent bonds in terms of atoms and sharing or transfer of electrons.
5. Describe the structure and properties of ionic compounds
6. Describe the structure and properties of molecular compounds.
2. Identify the properties of metals and non-metals (conductivity, luster and malleability [does it bend or break})
3. Define compound.
4. Describe ionic and covalent bonds in terms of atoms and sharing or transfer of electrons.
5. Describe the structure and properties of ionic compounds
6. Describe the structure and properties of molecular compounds.
Read page 19 - 20. View the video and notes below.
NOTES
- Covalent bonds involve sharing of electrons.
- It occurs between non-metals
- The structure formed is a molecule.
- The formula for a molecule (C2H5OH) represents the exact number of atoms.
- The attraction between molecules varies a lot. So molecular compounds can be solids, liquids or gases at room temperature, and they generally have lower melting points.
Read page 16 and make sure you can do targets 1 and 2.
Read Rock Salt on pages 17 - 18. View the video and notes below.
NOTES
- Ionic bonds involve a transfer of elections. Then the ions attract.
- It occurs between a cation (usually a metal) and an ion.
- The structure formed is a lattice structure of many interconnected atoms.
- The formula for an ionic compound represents a ratio of atoms (not an exact number)
- A crystal lattice structure has many strong, interconnected bonds between atoms, so it is very strong. Most ionic compounds are solids at room temperature, and they have high melting points.
Bond strength is tested by seeing how much energy it takes to break the bonds apart. Heat energy moves atoms or molecules apart. One way of comparing the strength between bonds is to look at melting points. The more energy required to melt a solid, the stronger the bonds.
At room Temperature, molecular compounds can be solids, liquids or gases, so their bond strengths vary, but they generally melt at lower temperature (think plastic - a molecular compound). At room temperature ionic compounds are all solids because they have high melting points. (think lava - ionic compounds)