Available Answers

1. 1.

   What is the differences between a chemical symbol and a chemical formula?

2. 2.

   How many atoms of zinc and chlorine are present in zinc chloride (ZnCl₂)?

3. 3.

   Write the formulae of the following compounds using the four-step method.

   1. Magnesium chloride (containing magnesium and chlorine)
   2. Zinc oxide (containing zinc zinc oxygen)
4. 4.

   Write the formulae of the following compounds using the four-step method.

   1. Lead nitrate (containing lead and nitrate; the valency of lead is 2)
   2. Copper sulphate (containing copper and sulphate; the valency of copper is 2)
5. 5.

   Multiple choice questions:

   1. The symbol of sulphur is __________.
      1. Ca
      2. S
      3. Cl
      4. K
   2. Which of the following is not an element?
      1. Mg
      2. Au
      3. CO₂
      4. Fe
   3. Which of the following is not a compound?
      1. ZnO
      2. AgCl₂
      3. AlCl₃
      4. He
   4. Which of these statements about compounds is false?
      1. The components of a compound are combined chemically.
      2. The components of a compound are mixed in a fixed ratio.
      3. The individual components of a compound retain their properties.
      4. Compounds and their components have different properties.
   5. Which of these is the correct way to write the formula of common salt?
      1. NACL
      2. NaCL
      3. NacL
      4. NaCl
   6. In SO₂ there are ____________ sulphur atom/atoms and __________ oxygen atom/atoms.
      1. 1, 2
      2. 2, 1
      3. 2, 2
      4. 1, 1
6. 6.

   Fill in the blanks:

   1. An atom of an element is represented using its chemical ______________.
   2. A ____________ is the smallest particle of a substance that can exist by itself in nature.
   3. The chemical _____________ of a compound consists of the symbols of the elements making up the compound with the number of atoms of each element written as a subscript to its right.
   4. The number of atoms present in a molecule is its ______________.
   5. The combining power of an element is known as its ________________.