Classification of Elements and Periodicity in Properties — Chemistry STD 11 Science — Question

Choose the wrong statement :

A trainee pilot was flying his plane in stratosphere. His senior advised him not to fly the aeroplane in the stratosphere.
Answer the following:

1. In your opinion, why the senior pilot advised his trainee pilot not to fly his plane in the stratosphere.
2. Write the possible reaction affecting stratosphere.

Refer to the periodic table given in your book and now answer the following questions:
Select three metals that can show disproportionation reaction.

What is the value of internal energy for 1 mole of a monoatomic gas?

Which of the following statements related to the modern periodic table is incorrect?

1. The p-block has 6 columns, because a maximum of 6 electrons can occupy all the orbitals in a p-subshell.
2. The d-block has 8 columns, because a maximum of 8 electrons can occupy all the orbitals in a d-subshell.
3. Each block contains a number of columns equal to the number of electrons that can occupy that subshell.
4. The block indicates value of azimuthal quantum number for the last subshell that received electrons in building up the electronic configuration.

Sodium forms a crystalline ionic solid with dihydrogen. The solid is non-volatile and non-conducting in nature. It reacts violently with water to produce dihydrogen gas. Write the formula of this compound and its reaction with water. What will happen on electrolysis of the melt of this solid?

Calculate number of atoms in 32u of He.

Why is standard enthalpy of formation of diamond not zero although it is an element?