Lesson learnt on element,compound

Elements are substances that cannot be broken down into simpler substances by chemical methods.

The different elements in a compound always join together in a fixed proportion by mass.

However, compounds are substances that could be broken down but it can only be broken down by chemical methods.

All the elements can be found in the Periodic Table. The columns of the Periodic Table are called group whereas the rows are called period.

Name of the element Symbol of the element

Aluminium Al

Zinc Zn

Copper Cu

Magnesium Mg

Mercury Hg

Iron Fe

Carbon C

Sulfur S

Chlorine Cl

Nitrogen N

Iodine I

Hydrogen H

Oxygen O

For those that were highlighted in red, they need a " 2 " below them when the questions did not mention the word element.

Elements are broken down into metals and non-metals.

Metals:Aluminium,calcium,copper,mercury,iron,zinc

Non-metals: Oxygen, hydrogen,helium,iodine,sulfur

Differences between metallic element and non-metallic element

Metallic element Non-metallic element

High melting point Low melting point

High boiling point Low boiling point

Good heat conductor Poor heat conductor

Good electrical conductor Poor electrical conductor

Ductile,malleable Brittle

High densities Low densities

Sonorous Not sonorous

Uses of some elements

Carbon

-exists in diamond,graphite,soot,charcoal

Diamond

-hardest

-attached to drills or saws for cutting concrete and drilling into rocks

Nitrogen

-unreactive element

-used in packaging of food

-used to make fertilisers

Sulfur

-non-metallic, yellow

-used to harden rubber used for making tyres

-used in pesticides and drugs

Iodine

-non-metallic

-sublimes when heated to form a violet vapour

-forms tincture of iodine as an antiseptic when dissolved in ethanol

Zinc

-coat iron sheet to make galvanised iron

-mixed with copper to form alloy, brass

Mercury

-the only metallic element that is a liquid at room temperature

-used in thermometers, fluorescent lamps and some dental fillings

Magnesium

-used to make fireworks

Reflections

Because of all these lessons I learnt, I could then be more aware of the elements around me and their uses. For example, if I ever had the chance to see magnesium, I would be more cautious and it was used to make fireworks and thus flammable.

I could also applied this to my daily life and after learning these concept, I could be more aware of the surroundings and the different types of elements.