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9th Chemistry Guess Paper

باب نمبر 1 - اہم مختصر جوابی سوالات

• Define industrial chemistry and analytical chemistry.
• How can you differentiate between organic and inorganic chemistry?
• Define mixture. How does a homogeneous mixture differ from a heterogeneous mixture?
• What is the relative atomic mass? How is it related to gram?
• What is meant by chemical properties? Give an example.
• Differentiate between molecule and molecular ion.
• Differentiate between homoatomic and heteroatomic molecules with an example.
• Differentiate between atom and ion.
• Define Avogadro’s number.
• Differentiate between bio-chemistry and physical chemistry.
• Differentiate between molecular mass and formula mass.
• How is the molecular formula derived from the empirical formula?
• What is meant by mole? State the number of moles in 9 grams of water/carbon.

باب نمبر 1 - اہم تفصیلی جوابی سوالات

• Define chemistry. Explain any five branches.
• List five characteristics by which compounds can be distinguished from mixtures.
• Write any five differences between molecules and atoms.

باب نمبر 2 - اہم مختصر جوابی سوالات

• Give two characteristics of cathode rays.
• What are the defects of Rutherford’s atomic model?
• Give two characteristics of canal rays.
• Write two characteristics of neutron.
• Write observations of Rutherford's experiment.
• Write down the electronic configuration of Al³⁺. How many electrons are present in its outermost shell?
• Define an isotope. Write two uses of isotopes.
• How can you prove that angular momentum is quantized?
• Differentiate between shell and sub-shell with examples of each.
• For what purpose is U-235 used?
• Explain the isotopes of hydrogen with a diagram.
• Define carbon dating.
• Write the electronic configuration of carbon and chlorine.
• What is meant by electronic configuration? How many electrons can accommodate in K, L, M, and N shells?

باب نمبر 2 - اہم تفصیلی جوابی سوالات

• How are cathode rays produced? What are its five major characteristics?
• Write a note on the discovery of protons. Also, write the properties of canal rays.
• How was the neutron discovered? Write down some properties of a neutron.
• Explain Bohr’s atomic theory. Also, write down its postulates.
• Describe Rutherford’s experiment for the discovery of the nucleus in an atom. Also, write his observations and results.
• Write down applications or uses of isotopes in different fields of life.

باب نمبر 3 - اہم مختصر جوابی سوالات

• Describe Newlands' law of octaves.
• Define Mendeleev’s periodic law.
• Why are noble gases not reactive?
• What do you mean by groups and periods in the Periodic Table?
• Define electron affinity. Write its trend in the period and group.
• Define the shielding effect.
• What is meant by atomic radius? Write its unit.
• Why is the second ionization energy higher than the first one?
• Define electronegativity. Write its trend in the period and group.
• Why does the size of an atom decrease in a period?
• Define ionization energy and write its unit.
• Write the trend of the shielding effect in period and group.
• Write down the modern periodic law.
• What are Dobereiner’s triads?

باب نمبر 4 - اہم مختصر جوابی سوالات

• Define the octet rule and the duplet rule.