Available Answers

1. 1.

   Complete the table given below - pertaining to classification of matter using the words.

   Impure substances, Pure substances, Compounds, Elements, Mixtures, Noble gases, Metalloids, Non-metals, Metals, Heterogeneous, Homogeneous

    

   

2. 2.

   State whether the following statements are true or false. If false write the correct statement.

   1. An element is a pure substance - made up of - two or more kinds or atoms.
   2. A compound is a pure substance formed by combination of - two or more atoms combined together in any ratio.
   3. Mixtures are impure substances mechanically mixed together in any ratio.
3. 3.

   Draw a diagram of an atom & label it as follows:

   1. Nucleus - containing five protons & six neutrons.
   2. Inner orbit - containing two electrons.
   3. Outer orbit - containing three electrons.
      Label the - nucleus, proton, neutron, electron, orbit
4. 4.

   Name the following, from the elements from atomic numbers 1 to 20 of the Modern Periodic Table

   1. Two noble gases other than argon
   2. Three non-metals which are solids at room temperature
   3. A metalloid - other than silicon
5. 5.

   Name the following - pertaining to characteristics of metals, non-metals, metalloids & noble gases.

   1. A metal - liquid at room temperature.
   2. A lustrous non-metal, other than graphite.
   3. A non-metal - which is a good conductor of electricity.
   4. A mono-atomic element - which shows properties of both metals & non-metals & has the symbol - 'Sb'
   5. A mono-atomic element - which is chemically inert & present in traces in the atmosphere & has the symbol - 'Xe'
   6. A metal - which is non-malleable & non-ductile, beyond a certain temperature.
   7. A non-metal which - forms a coloured gas.
   8. A metal which burns - with a dazzling white light.
   9. A metal while Latin name is Aurum.
   10. A non-metal - which burns in air forming violet vapours.
   11. A non-metal - which constitutes about 79% of the atmospheric air.
6. 6.

   State whether the following statements pertaining to molecules are true or false. If false write the correct statement.

   1. Atoms of the same element or different elements - combine to form a molecule.
   2. Atomicity is the number of elements that join totgether forming a molecule of that element.
   3. Hydrogen is a mono-atomic molecule.
   4. Helium is a diatomic molecule.
   5. Ozone is polyatoic - witth atomicity three.
   6. Chlorine is a coloured gas with atomicity one.
   7. The atomicity of phosphorus & ozone is the same.
   8. The number of atoms in a molecule of oxygen is one.
   9. Water is one example of a molecule formed from atoms of different elements.
   10. The molecule of nitric oxide contains 1 atom of nitrogen & two atoms of oxygen.
   11. The molecule of zinc nitrate contains 1 atom of zinc, two atoms of nitrogen & three atoms of oxygen.