Grade 8 Chemistry Properties of Material-Presentation.pdf

Chemistry Grade 8 Content with Properties of Matter

1. Properties of Materials
Structure of Matter | PPT
W. Thilan Atalugama

2. Atomic structure and the Periodic Table
Bing Videos

3. First 20 elements and symbols

4. •Left to Right and Top to Down -Mass of Atoms Increase
•Atomic Number= No of Protons
•Mass Number = No of Protons + No of Neutrons
•Protons have a positive (+) charge. Electrons have a negative (-)
charge.
•An atom has no overall charge, because the number of protons is
the same as the number of electrons.

6. How to remember the order
•Hydrogen (H): Lightest element, colorless, odorless, highly flammable gas.
•Helium (He): Colorless, odorless, inert gas, second lightest element.
•Lithium (Li): Soft, silvery-white metal, highly reactive, used in batteries.
•Beryllium (Be): Hard, gray metal, high melting point, used in aerospace materials.
•Boron (B): Metalloid, black-brown, used in borosilicate glass and detergents.
•Carbon (C): Nonmetal, found in all organic life, forms allotropes like diamond and graphite.
•Nitrogen (N): Colorless, odorless gas, makes up 78% of Earth's atmosphere.
•Oxygen (O): Colorless, odorless gas, essential for respiration, makes up 21% of Earth's
atmosphere.
•Fluorine (F): Pale yellow gas, highly reactive, used in toothpaste and Teflon.
•Neon (Ne): Colorless, inert gas, used in neon signs.
•Sodium (Na): Soft, silvery-white metal, highly reactive, used in table salt.
•Magnesium (Mg): Shiny gray metal, used in lightweight alloys and fireworks.
•Aluminum (Al): Silvery-white metal, lightweight, used in cans and foil.
•Silicon (Si): Metalloid, used in semiconductors and glass.
•Phosphorus (P): Nonmetal, exists in several forms, used in fertilizers.
•Sulfur (S): Yellow nonmetal, used in sulfuric acid and vulcanization of rubber.
•Chlorine (Cl): Greenish-yellow gas, used in disinfectants and PVC.
•Argon (Ar): Colorless, inert gas, used in light bulbs and welding.
•Potassium (K): Soft, silvery-white metal, highly reactive, used in fertilizers.
•Calcium (Ca): Soft gray metal, essential for bones and teeth, used in cement and plaster.

9. •This measure of the mass for a fixed volume of a substance is
called the density. The density is given using the unit g/cm3.
•The density of iron is 7.87 g/cm3 and that of sodium 0.97 g/cm3.
So, iron is more dense than sodium.

10. Arranging electrons
J.J. Thompson and Ernest Rutherford Model

11. In 1913, the Danish scientist Niels Bohr
Electrons Move in
Different Energy levels
Noble Prize Winner

12. Electronic structure-The electrons are arranged
in electron shells around the nucleus.
Electrons are held in place by electrostatic forces.
arrangement for a boron atom can be written as 2,3
Electronic arrangement for a
boron atom can be written as
2,3
The first shell always fills up
before electrons go into the
second shell

15. Reactivity and displacement reactions

17. Answers

18. Using the reactivity series and displacement
reactions
•Thermite Reaction: Aluminium displaces iron from iron
oxide, producing molten iron and aluminium oxide.
•Exothermic: The reaction releases a lot of heat, melting
the iron.
•Application: Used to weld railway rails by placing the
reaction mixture on the rails.
•Ignition: Started using another exothermic reaction
between magnesium powder and barium nitrate.

20. Displacement with Carbon:
• Carbon can displace metals like zinc, iron,
tin, and lead from their ores.
•Historical Discovery: Around 3500 years
ago, people discovered that heating iron
ore with charcoal (carbon) produced
molten iron.
•Modern Application: This reaction is now
carried out on a large scale in blast
furnaces.
•Reaction: Iron oxide reacts with carbon to
form iron and carbon dioxide.
•Equation:
iron oxide + carbon → iron + carbon dioxide

22. Answers