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Today we are going to talk about How to write Chemical Formulae for Compounds.  We will go through briefly about symbol, Formula, and Valency and then dig deeper in to each of these.  So let us get started –

Symbol

It is the abbreviation of English or Latin name of element represented by first letter or first letter in capital with any other letter in small
Eg.  H, Fe, C, Cl

Formula

It is the abbreviation of the molecules represented by symbols and numericals.
Eg.  H2, H2O

Valency

It is the combining capacity of an element with the other element is known as valency and it is determined by the number of hydrogen or chlorine atoms that will combine with one atom of element
Eg.  CH4 – methane.  Here one atom of carbon is combined with four atoms of hydrogen.  Valency of carbon is 4

 

English Name           Latin Name          Symbol               Valancy

  1. Sodium                   Natrium                   Na                              +1
  2. Potassium             Kalium                      K                                 +1
  3. Calcium                Calcium                     Ca                               +2
  4. Magnesium         Magnesium               Mg                               +2
  5. Zinc                      Zincum                       Zn                               +2
  6. Aluminum         Aluminum                  Al                                 +3
  7. Copper                 Cuprum                    Cu                               +1 , +2
  8. Iron                       Ferrum                     Fe                               +2 , +3
  9. Mercury            Hydragyrum               Hg                              +1 , +2
  10. Gold                    Aurum                        Au                               +1 , +3
  11. Silver                 Argentum                   Ag                                +1
  12. Tin                     Stannum                     Sn                               +2 , +4
  13. Lead                  Plumbum                    Pb                               +2 , +4
  14. Antimony         Stibium                        Sb                              +2 , +4
  15. Barium              Barium                        Ba                              +2
  16. Cadmium          Cadmium                   Cd                               +2
  17. Chromium       Chromium                   Cr                             +3

 

              Valency of Non – metals :

Elements Valency
C ( Carbon )   -4
S ( Sulphur )   –  4 , – 6
N ( Nitrogen )   – 1 ,- 2 , -3 ,- 4 ,- 5
F ( Fluorine )   – 1
Cl ( Chlorine )   – 1
Br ( Bromine )   – 1
I ( Iodine )   – 1
O ( Oxygen )   – 2
P ( Phosphorus )   – 3 , -5
H ( Hydrogen )   + 1

 

Radical : A group of element behave like a single element is called Radical .

                               Radical                    Formula                      Valency
                               Ammonium                -NH4                             +1
                               Nitrate                        -NO3                                  -1
                               Nitrite                         -NO2                             -2
                               Nitride                         -N                                  -3
                               Sulphate                      -SO4                              -2
                               Bisulphate                   -HSO4                            -1
                               Sulphide                      -S                                    -2
                               Thiosulphate                -S2O                          -2
                               Carbonate                    -CO3                               -2
                               Bicarbonate                 -HCO3                           -2
                               Phosphate                    -PO4                           -3
                               Borate                          -BO3                             -3
                               Fluoride                        -F                                -1
                               Chloride                       -Cl                               -1
                               Bromide                       -Br                               -1
                               Iodide                           -I                                 -1
                               Oxide                           -O2                               -2
                               Chromate                     -Cr2O4                   -2
                               Permanganate              -MnO4                          -1
                               Hydroxide                    -OH                              -1

 

You are reading How to write Chemical Formulae for Compounds…..

 Formula:

 

  1. Sodium Chloride :        Na Cl           Na1    ⤩    Cl1           Na 1 Cl 1        NaCl
  2. Potassium Chloride :    K Cl             K1 ⤩   Cl1                 K1  Cl1               KCl
  3. Calcium Chloride :          Ca C l        Ca2 ⤩ Cl1                Ca1 C l 2              CaCl2
  4. Magnesium Chloride :    Mg Cl        Mg2 ⤩ Cl1                  Mg1 Cl2          MgCl2
  5. Aluminum Chloride :       Al Cl          Al3 ⤩ Cl1                    AlCl3            AlCl3
  6. Zinc Chloride :                    Zn Cl         Zn2 ⤩ Cl1               Zn1 Cl2            ZnCl2
  7. Calcium Oxide :                 Ca O            Ca2 ⤩ O2                  Ca2 O2           Ca O
  8. Sodium Oxide :                 Na O              Na1 ⤩ O2                Na2 O1           Na2 O
  9. Potassium Oxide :            K O                 K1 ⤩ O2                    K2 O1           K2O
  10. Magnesium Oxide :          Mg O              Mg2 ⤩ O2                   Mg2 O2          MgO
  11. Zinc Oxide :                        Zn O               Zn2 ⤩ O2                Zn2 O2          Zn O
  12. Aluminum Oxide :             Al O              Al3 ⤩ O2                        Al2 O3         Al2 O3
  13. Nitrous Oxide :                   N O                  N1 ⤩ O2                  N2 O1          N2 O
  14. Nitrogen Monoxide :          N O               N2 ⤩ O2                    N2 O2           N O
  15. Nitrogen Trioxide :             N O               N3 ⤩ O2                    N2 O3          N2 O3
  16. Nitrogen Dioxide :              N O               N4 ⤩ O2                     N2 O4          N O2
  17. Nitrogen pentoxide :          N O               N5 ⤩ O2                     N2 O5          N2 O5
  18. Sulphur Dioxide :                S O                S4 ⤩ O2                    S2 O4           S O2
  19. Sulphur Trioxide :               S O               S6 ⤩ O2                      S2 O6              S O3

 

-OUS Compound:  When the metal shows lower valency.

-IC Compound: When the metal shows higher valency .

 

E.g : i) Cuprous Oxide – Cu1 O2           Cu1 ⤩ O2            Cu2 O1         Cu2O

Cupric Oxide –  Cu2 O2         Cu2 ⤩ O2             Cu2 O2        CuO

ii) Ferrous Oxide – Fe2 O2              Fe2 ⤩ O2                Fe2 O2              FeO

Ferric Oxide –         Fe3 O2         Fe3 ⤩ O2              Fe2 O3             Fe2O3

Note : Fe O + Fe2 O3         Fe3 O4 ( Rust )

i.e. Ferrous Oxide + Ferric Oxide – Ferrosoferric Oxide           Fe3O4

 

  1. Sodium Hydroxide:         Na (OH)           Na1 (OH)1          NaOH
  2. Patassium Hydroxide:       K (OH)           K1 (OH)1            KOH
  3. Calcium Hydroxide:           Ca2 (OH)1      Ca(OH)2
  4. Zinc Hydroxide:                 Zn2 (OH)1        Zn(OH)2
  5. Magnesium Hydroxide:    Mg2 (OH)1        Mg(OH)2
  6. Aluminium Hydroxide:      Al3 (OH)1        Al(OH)3
  7. Ammonium Hydroxide:     NH41 OH1       NH4OH
  8. Sodium Hydroxide:             Na1 OH1            Na1OH1
  9. Calcium Sulphate:                Ca2 SO42           CaSO4
  10. Magnesium Sulphate:           Mg2 SO4 2       MgSO4
  11. Zinc Sulphate:                         Zn2 SO42         ZnSO4
  12. Copper Sulphate:                   Cu2 (SO4)2       CuSO4
  13. Calcium Nitrate:                    Ca2 (NO3)1        Ca (NO3)2
  14. Magnesium Nitrate:              Mg2 (NO3)1     Mg(NO3)2
  15. Zinc Nitrate:                             Zn2 (NO3)1     Zn(NO3) 2
  16. Calcium Nitrite:                      Ca2 (NO2)2         CaNO2
  17. Magnisium Nitrite:                 Mg2 (NO2)2      MgNO2
  18. Calcium Nitride:                      Ca2 N3               Ca3N2
  19. Aluminium Nitride:                 Al3 N3                 AlN
  20. Calcium Carbonate:               Ca2 CO32            CaCO3
  21. Potassium Permanganate:    K1 (Mn O4)1           KMnO4
  22. Potassium Dichronate:            K1 (Cr2 O7)2      K2Cr2 O7
  23. Sodium Peroxide:  Na2O2
  24. Hydrogen Peroxide:  H2O2
  25. Potassium Chlorate:  KClO3
  26. Potassium Ferrocyaside:  K4[Fe (CN)]6
  27. Potassium Dichromate:  K2Cr2O7
  28. Potassium Permanganate:  KMnO4
  29. Potassium Chlorate:  KClO3
  30. Sodium Peroxide:  Na2O2
  31. Hydrogen Peroxide:  H2O2

If you have enjoyed reading this post How to write Chemical Formulae for Compounds.  I would be very grateful if you would help it to spread by sharing on social media like Facebook, Twitter, Google+, by clicking on the share buttons below.  If you have any questions or comments, feel free to ask them in the comment section below.   I will see you in my next blog post.

PpG

 

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Hi viewers My name is Partha Pratim Goswami, (PpG) I am a teacher by profession. I have been teaching biology, chemistry and physics, sometimes mathematics also for last sixteen years. I would like to share my entire experience with all the viewers across the world through YouTube, which I think is an amazing platform to share all my experiences.

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