Elements

Hey welcome back! Today, we would learning about elements!!(:

What is element?

• a substance which cannot be split into two or more by chemical reaction.
• every element is given a name and chemical symbol
• 1o9 elements are discovered so far
• 92 are natural element while others are man-made
• Most elements are found combined with other elements in the form of ores and minerals

Classification of elements:
http://www.bpc.edu/mathscience/chemistry/images/periodic_table_of_elements.jpg

Elements are classified according to their chemical properties into a chart called a Periodic table which can be seen from the above link.

In the periodic table:

• Each vertical column is called a group
• Each element in a group has a similar chemical properties
• Each group has its own unique properties
• Each horizontal row is called a period
• Elements from right to left show a gradual change from metallic elements to non-metallic elements

Physical properties of Metallic and non-metallic elements

Metallic elements Non-metallic elements
1. High boiling and melting points. 1. Low boiling and melting points
2. Good conductors of heat 2. Poor conductors of heat
3. Good conductors of electricity 3. Poor conductors of electricity
4. Ductile ( can be drawn into wires) 4. Snap easily
5. Malleable (can be beaten into shapes without breaking) 5. Brittle( easily broken)
6. Shiny 6. Dull in appearance
7. High in density 7. Low in density
8. Sonorous 8. Not sonorous

Uses of some non-metallic elements:

1. Carbon Uses: Pencil lead, fuel, constitutes living tissues
2. Nitrogen Uses: fertilizers, freezing agent for food, constitutes plants and animal proteins
3. Sulfur Uses: harden rubber, pesticides, drugs, fireworks
4. Iodine Uses: antiseptic
5. Oxygen Uses: respiration, combustion
6. Chlorine Uses: bleaching powder, kills bacteria, used in making plastics
7. Fluorine Uses: prevents tooth decay
8. Silicon Uses: transistors, manufacture of steel

Uses of some metallic elements:

1. Zinc Uses: to coat iron sheets to make galvanized iron
2. Mercury Uses: thermometers, fluorescent lamps, dental fillings
3. Magnesium Uses: used to distress flares, fireworks
4. Aluminum Uses: aeroplane parts, dink cans, cooking utensils, ladders
5. Copper Uses: electrical wires, water pipes, switches, coins, tanks
6. Calcium Uses: for the body to grow strong teeth and bones
7. Iron Uses: manufacture of steel, railings, grills, cooking utensils
8. Lead Uses: lead shots, accumulators
   

Okay, that;s all for today's lesson. Hope you and enjoy and remember to tune next week for the lesson on compounds and mixture! (: