Main Element In The Earth’s Crust

SM Sains Kimia Analisis Dan Persekitaran

Lecturer: PUAN MAISARAH BINTI JAAFAR

Group members: ABDUL RAHMAN BIN YUSUF UK26406

ZAIIMAH BINTI ROZMAN UK25649SITI SOLEHA BINTI MUSTAFFA UK24901

WAN AZWIRA BINTI AB GHANI @ WAN AHMAD UK26257

NURUL SYAZDIANA BINTI MOHD ZUKI UK26258

Elements Approximate % by weight

Oxygen (O) 46.6

Silicon (Si) 27.7

Aluminum (Al) 8.1

Iron (Fe) 5.0

Calcium (Ca) 3.6

Sodium (Na) 2.8

Potassium (K) 2.6

Magnesium (Mg) 2.1

Abundances of the Elements in the earth’s

crust

Silicon Common element in the earth’s crust Shiny, dark grey with a tint of blue Never found in its natural state, but

rather in combination with oxygen as a silicate ion (SiO) in silica-rich rocks

Example: obsidian, granite, diorite, and sandstone

Recovered from an abundant resource: sand

Most pure sand is quartz, silicon dioxide (SiO2)

Silicon with oxygen• Silicon occurs mainly in nature as the oxide

and silicates.• Silicates are compound containing a silicon

bearing an anion.• Silicon reacts with oxygen become silicates,  SiO .• Minerals containing silica, known as silicates• Examples: • quartz (SiO2) and olivine (FeSiO4) common components of beach sand.

Aluminium Reactive metal, and does not

occur in the metallic state in nature

All of the earth's aluminum has combined with other elements to form compounds

Two of the most common compounds: alum

Example: potassium aluminum sulfate (KAl(SO4)2·12H2O), and aluminum oxide (Al2O3)

Bauxite Mainly aluminum oxide (Al2O3) Most important ore Bauxite production - processed first

into alumina, and then into aluminium by electrolysis

Used in cement, chemicals, face makeup, soda cans, dishwashers, siding for houses

They were formed by lateritization of various silicate rocks

Example: granite, gneiss, basalt, syenite, and shale

Calcium Soft grey alkaline earth metal A silvery metallic element that must be

extracted by electrolysis from a fused salt

Example: calcium chloride Once produced, it rapidly forms a grey-

white oxide and nitride coating when exposed to air

Calcium metal reacts with water, evolving hydrogen gas at a rate rapid enough to be noticeable, but not fast enough at room temperature to generate much heat

Calcium with Water Ca (s) + 2H2O (g) Ca(OH)2 (aq) + H2 (g) Under normal conditions calcium carbonate is

water insoluble When carbon dioxide is present carbonic acid is

formed, affecting calcium compounds. The reaction mechanism for carbon weathering is:

H2O + CO2 H2CO3   & CO32- + H2CO3  Ca(HCO3)2

And the overall reaction :CaCO3 (s) + CO2 (g) + 2H2O (l) Ca2+ (aq) + 2 HCO3- (aq)

The product is calcium hydrogen carbonate.

Sodium Occur as: Salt Amphibole Zeolite Forms a very important part of blood

plasma. Allows our bodies to maintain the

right blood chemistry and the correct amount of water in our blood.

Essential for normal functioning of our nervous system

Reaction of Sodium

It has two reaction: With water:2Na(s) + 2H2O → 2NaOH(aq) + H2(g)* form sodium hydroxide With air:

1. 2Na(s) + O2 (g) → 2Na2O2(s)2. 4Na(s) + O2 (g) → 2Na2O(s)* form sodium peroxide and sodium oxide

Potassium Great importance for soil health,

plant growth and animal nutrition. Occurs in:

1. Orthoclase (potassium feldspar): Common rock forming mineral

2. Granite3. Sylvite4. Carnallite

Potassium deficiency caused restricted growth, reduced flowering, lower yields and lower quality produce. 

Reaction of Potassium

Simple two reaction: With water:

2K (s) + 2H2O (l) -> 2KOH (aq) + H2 (g)* form potassium hydroxide

With air:K(s) + O2(g) → KO2(s)*form potassium superoxide

Magnesium For the proper growth, formation

and function of our bones and muscles.

Control how our muscles contract. Essential in allowing your body to

control insulin levels in your blood. 

Present in seawater: Mg2+ (second most abundant cation in seawater)

Reaction of Magnesium

With water vapor, form magnesium hydroxide and hydrogen gas:Mg (s) + 2H2O(g) →Mg(OH)2(aq) + H2(g)

With water:Mg (s) + 2H2O(g) -> Mg(OH)2(aq) + H2(g)* form magnesium hydroxide

With air:1. 2Mg(s) + O2 (g) → 2MgO(s)2. 3Mg(s) + N2 (g) → Mg3N2 (s)* form magnesium oxide and magnesium nitride

References http://

education.jlab.org/glossary/abund_ele.html

http://www.windows2universe.org/earth/geology/crust_elements.html

http://chemistry.about.com/od/elementfacts/a/silicon.htm

http://www.webelements.com/potassium/chemistry.html