Class 9 Chemistry Chapter 4 Question Answer
Important Notes of Class 9 Chemistry Chapter 4 Question Answer English Medium written by Professor M. Shahid Suib. These notes are very helpful in the preparation of Structure of Molecules Class 9 for students of the 9th class Chemistry English Medium and these are according to the paper patterns of all Punjab boards.
Summary and Contents:
Topics which are discussed in the notes are given below:
- Here are the detailed Class 9 Chemistry Chapter 4 Question Answer to help you prepare for your exams.
- Complete Exercise MCQs of Chapter No.4 Structure of Molecules
- Complete Exercise Short Questions with Answers of Chapter No.4 Structure of Molecules
- Why do atoms react?
- Differentiate between a lone pair and a Bond pair of electrons?
- What is the difference between polar and nonpolar covalent bonds?
- Metals are good conductors of electricity. Why?
- Ionic compounds conduct electricity in solution or molten form. Why?
- Why does ice float on water?
- Why alcohol is soluble in water?
- What are intermolecular forces? Give one example.
- What do you mean by malleability and ductility?
- Define chemical bonds. Write the names of four different types.
- Define the octet rule and duplet rule.
- Write any two properties of ionic compounds. (Also a long question)
- Write any two properties covalent compound. (Also a long question)
- Write two physical properties of metals. (Also a long question)
- Define the co-ordinate covalent bond. Give one example.
- Define covalent bond. Give one example.
- What is a metallic bond?
- Define hydrogen bonding. Show the hydrogen bonding in water molecules.
- Describe the major properties of metals.
- State four properties of ionic compounds.
- State four properties of covalent compounds.
- Define the ionic bond and explain it with the help of an example.
- Define the ionic bond. Explain it with the help of an example.
- How coordinate covalent bond is formed? Explain with examples.
- Define covalent bond. Explain its types with the help of examples.
- Define hydrogen bonding. How does it affect the physical properties of compounds?
- Polar and Non-polar Covalent Bond: If a covalent bond is formed between two similar atoms (homo-atoms), the shared pair of electrons is attracted by both the atoms equally. Such type of bond is called non-polar covalent bond. These bonds are formed by equal sharing of electron pair between the two bonding atoms. This type of bond is called a pure covalent bond. For example, bond formation in H2 and CI2.
- If the covalent bond is formed between two different types of atoms (hetro- atoms) then the bond pair of electrons will not be attracted equally by the bonded atoms. One of the atoms will attract the bond pair of electrons more strongly than the other one. This atom(element) will be called as more electronegative.
- When there is difference of electronegativity between two covalently bonded atoms, there will be unequal attraction for the bond pair of electrons between such atoms. It will result in the formation of polar covalent bond. The difference between electronegativities of hydrogen and chlorine is 1.0. As the electronegativity of chlorine is more, it attracts the shared pair of electron towards itself with a greater force. A partial negative charge is therefore created on chlorine and in turn a partial positive charge on hydrogen due to electronegativity difference. It creates polarity in the bond and is called polar covalent bond.
- The delta (sigma) sign indicates partial positive or partial negative charge that is developed due to unequal sharing of shared pair or bonded pair of electrons. The compounds resulting from polar covalent bonds are called polar compounds. For example: water, hydrogen fluoride and hydrogen chloride.
- By using electronegativity values, it is possible to predict whether a chemical bond will be ionic or covalent in nature. A bond formed between elements of high electronegativity (halogen group) and elements of low electronegativity (alkali metals) are ionic in nature. There is complete transfer of electrons between them. The bond between elements of comparable electronegativities will be covalent in nature as the bond between carbon and hydrogen in methane, or nitrogen and hydrogen in ammonia.