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CHEMISTRY, M1 EQ-Bank 7

Explain, with the use of a diagram or otherwise, why the oxide ion has a valency of minus 2.   (2 marks)

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  • An oxide ion is the ion of the element oxygen \(\ce{(O)}\), atomic weight 16.
  • An oxygen atom has 8 electrons and 8 protons. It has 2 electrons in its inner shell and 6 electrons in its valence (outer) shell.
  • An oxygen atom can gain 2 electrons to form a stable octet in its valence shell and therefore has a valency of minus 2.

Show Worked Solution
  • An oxide ion is the ion of the element oxygen \(\ce{(O)}\), atomic weight 16.
  • An oxygen atom has 8 electrons and 8 protons. It has 2 electrons in its inner shell and 6 electrons in its valence (outer) shell.
  • An oxygen atom can gain 2 electrons to form a stable octet in its valence shell and therefore has a valency of minus 2.

CHEMISTRY, M1 EQ-Bank 6

What are the valencies of the following simple and polyatomic ions

  1. Phosphate \((\ce{PO4})\)  (1 mark)
  2. Zinc \((\ce{Zn})\)  (1 mark)

  3. Carbonate \((\ce{CO3})\)  (1 mark)

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a.   Valency: Phosphate \((\ce{PO4}) = 3^{-}\)

b.  Valency: Zinc \((\ce{Zn}) = 2^{+}\)

c. Valency: Carbonate \((\ce{CO3}) = 2^{-}\)

Show Worked Solution

a.   Valency: Phosphate \((\ce{PO4}) = 3^{-}\)

b.  Valency: Zinc \((\ce{Zn}) = 2^{+}\)

c. Valency: Carbonate \((\ce{CO3}) = 2^{-}\)

CHEMISTRY, M1 EQ-Bank 5

What are the valencies of the following simple ions

  1. Barium \((\ce{Ba})\)   (1 mark)

  2. Phosphide \((\ce{P})\)  (1 mark)

  3. Silver \((\ce{Ag})\)  (1 mark)

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a.   Valency: Barium \((\ce{Ba}) = 2^{+}\)

b.  Valency: Phosphide \((\ce{P}) = 3^{-}\)

c.  Valency: Silver \((\ce{Ag}) = 1^{+}\)

Show Worked Solution

a.   Valency: Barium \((\ce{Ba}) = 2^{+}\)

b.  Valency: Phosphide \((\ce{P}) = 3^{-}\)

c.  Valency: Silver \((\ce{Ag}) = 1^{+}\)