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Sunday, 9 October 2016

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Elements, metals, valency numbers and symbols.



properties of elements





An element is a substance which cannot be split or broken down into two or more simpler units of substance by an ordinary chemical process.



    Scientists have discovered over 100 elements on earth and these includes substances like: iron , gold, tin, oxygen, as well as unfamiliar ones like scandium , americium , xenon etc.
     There are abbreviation or symbols to represent element e.g. O for oxygen, Al for Aluminium, mg for magnesium, Na for sodium, Fe for Iron etc. Most of these elements are derived from the names of these elements while few are derived from Latin names e.g. Natrium ( Na), ferrium (Fe) etc.







   Classification of Element.
Elements can be grouped in the form of periodic tables as follows:

1) Reactive metals : Sodium, potassium, calcium, magnesium etc.

2) Transition metals: Manganese, zinc , copper, nickel etc.

3) Inner transition metals: Europium , Uranium, neptunium, Lawrencium etc.

4) Reactive non-metals: chlorine, fluorine , nitrogen, oxygen etc.

5) Non reactive non- metals: Helium , Neon, argon, krypton, Radon, xenon (noble gases)



                               Element



Symbol



Latin
                               Hydrogen


H


                               Helium


   He


                               Lithium


    Li


                               Beryllium


   Be


Boron

   B


                               Carbon


   C


                               Nitrogen


   N


                               Oxygen


   O


                               Fluorine


   F


Neon

   Ne


                              Sodium


   Na

Natrium
                              Magnesium


   mg 


                             Aluminium


   Al


Silicon

   Si


                             Phosphorus


   P


                             Sulphur


   s


           
Chlorine



  cl


Argon

  Ar


                             Potassium


   k

k atrium
                              calcium



 ca




Valency of Element and Radicals

Valency is the combining power of an element. However, the number of miles of hydrogen ion that would combine with one Molecules of an element gives the valency of that element. For Instance the valency of the following hydride's from their formula.


                    Hydride
Valency
              LiH
1
              Be H2
2
               NH3
3
               H2O
2
               CH4
4



Valency of some elements


Element
Symbol
Valency
 Aluminium
Al
+3
 Bromine
Br
-1
 Barium
Ba
+2
 Calcium
Ca
                        +2
 Carbon
                C
                         +2 or +4
Chloride
                Cl
                          -1
Copper
                Cu
                          +1 or +2
Manganese
                Mn
                          +2, +4 or +7
Gold
                 Au
                           +1
Argon
                  Ar
                             -






Radicals

These are formed when two or more atoms of different element come together and reacts as a units. Move over, the radicals May be charged and have oxidation number which are usually represented by the net number of positive and negative charges that they carry.




Radical
Formular
Valency
Ammonium
NH4+
                 +1
Hydroxide
OH-
-1
Trioxonitrate (v)
NO3-
                  -1
Dioxonitrate (iii)
NO2-
                  -1
Trioxocarbonate(iv)
CO32-
                  -2
Trioxosulphate(iv)
SO32-
-2
Tetraoxosulphate(vi)
SO42-
-2
Hydrogentrioxocarbonate(iv)
HCO3-
-1





Question
  Write the formula of the following compounds.
1) Sodium tetraoxosulphate(vi)
2) Potassium trioxocarbonate (iv)
3) Aluminium oxide
4) calcium chloride
5) Hydrogen sulfide
6) Calcium hydrogen trioxocarbonate (iv)
7) Lithium hydride
8) water
9) Ammonium tetraoxosulphate (vi)

READ MORE: Compounds and mixtures



Solution

1)  Na +    SO42-    ↔   Na2SO4
2)  K+       CO32-    ↔    K2CO3
3)  Al 3+  O2-        ↔     Al2O3
4)  Ca2+   Cl-        ↔  CaCl2           
5)  H     S2-        ↔    H2S
6)  Ca 2+ HCO3-  ↔    Ca(HCO3)2
7)  H+      O2-         ↔    H2O

8)  NH4+   SO42-   ↔    (NH4)2 SO4






conclusion
   This has been a brief introduction of Chemical elements and valency. You also learnt how to write chemical compound. If you have any questions, just comment. All comments are appreciated.

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