JEE Main and CBSE Board Exams Numericals

Properties of Alkaline metals:

1. Predict the reactivity of the following metals: Sodium (Na), Potassium (K), Rubidium (Rb) and Cesium (Cs). Explain based on their atomic size and ionization energy.

2. Arrange the following elements in the increasing order of acidic character of their oxides: K, Ca, Al and Si.

3. State the trend of the following properties of the elements in Group 1 along the period:

• (a) Atomic size
• (b) Ionisation energy
• (c) Number of valence electrons.

4. Account for the following:

• (a) BeH2 is a covalent molecule while MgH2 is an ionic solid.
• (b) LiF is soluble in organic solvents while MgF2 is insoluble.
• (c) LiCl is deliquescent while CsCl is not.

Properties of Halogens:

1. Arrange the following compounds in the increasing order of their boiling points: HI, HF, HCl, HBr, CH4

2. Name the products formed when the following halides react with water:

• CaF2
• CsBr
• AlCl3
• NaI

3. Why is fluorine a gas at room temperature while potassium chloride is a solid with high melting and boiling points?

4. Account for the following:

• (a) Fluorine gas reacts with water to produce HF acid while iodine produces HIO3 acid.
• (b) Chlorine reacts with hot and concentrated sodium hydroxide to produce sodium chlorate while cold and dilute sodium hydroxide produces sodium hypochlorite.
• (c) Copper metal dissolves in concentrated HNO3 but not in dilute HNO3.

Periodic Properties

1. Identify the element X from the following properties:

• It has a low ionisation energy and large atomic size.
• It forms basic oxides.
• It is a solid at room temperature.
• Its hydroxide is insoluble in water.

2. Element X forms an ionic compound with Y and covalent compound with Z. Element Y has a greater electronegativity than element Z. What will be the trend of the electronegativity of X, Y, and Z?

3. Arrange the elements Na, Mg, Al and Si in the order of their increasing:

• (a) Atomic size
• (b) Ionisation energy
• (c) Number of valence electrons

Chemical Bonding

1. Draw the Lewis structures for the following compounds:

• CO2
• SO2
• NH3
• CH4

2. State the type of hybridisation of the central atom in the following compounds:

• BF3
• H2O
• CH4
• NF3

3. Predict the shape and bond angle for the following molecules:

• BF3
• H2O
• CO2
• NH3

Remember:

• Always try to focus on concepts and formulae.
• Practice numerical problems as much as you can.
• Revise regularly to retain concepts and formulae.