Page 22 - E-Science Prep1 2024-2025 t2 Unit1_Neat - Copy

• Any salt begins with the cation then followed by the anion.

-ve : MgCl NaCl
nonmetal
Magnesium2 chloride Sodium chloride
ion:

a) Positive metal ion with: -ve Mg(NO3)2 CuSO4
atomic
group Magnesium nitrate

Unhydrous copper sulphate

b) Positive atomic group with: -ve : NH4Cl
nonmetal
All –ve ions form salts Ammonium chloride
except the – oxygen ion ion:
(NH4)2CO3
(O-- Oxide) -ve
atomic Ammonium carbonate
Chemical formula: group (NH4)2SO4

Ammonium carbonate

How can you write the chemical formula for the compound?

1- Write the name of the compound. Starts from left with Ends on right
2- Write the symbol of each element or metal / hydrogen / with non-metal/

atomic group. + atomic gp. - atomic gp.
3- Write the valency under each symbol.
4- Exchange their valences after The total charge
of the salt = zero
simplifying them:
5- Write the symbols with their

exchanged numbers but note:

• Don’t write 1.

• The atomic gp. is between brackets
if their number is more than 1.

37

Second Term