Class 11th

Assertion: Symmetrical distribution of electrons leads to stability.

Reason: Electronic distribution of an element is important to understand and explain the chemical behaviour of the element.

Assertion: Chromium and copper have five and ten electrons in 3d orbitals rather than four and nine as their position would have indicated with two-electrons in the 4s orbital.

Reason: Fully filled and half-filled orbital shave extra stability that is, lower energy.

Write the structures and names of products obtained in the reactions of sodium with a mixture of 1-iodo-2-methylpropane and 2-iodopropane.

Assertion: Both the exact position and exact velocity of an electron in an atom cannot be determined simultaneously (Heisenberg uncertainty principle).

Reason: The path of an electron in an atom can be determined accurately.

The relative reactivity of 1°, 2°, 3° hydrogen's towards chlorination is 1 : 3.8 : 5. Calculate the percentages of all monochlorinated products obtained from 2-methylbutane.

Assertion: Classical mechanics fails when applied to microscopic objects like electrons, atoms, molecules etc.

Reason: Classical mechanics ignores the concept of dual behaviour of matter especially for sub-atomic particles and the uncertainty principle.

Assertion: Rainbow is a line spectrum.

Reason: In rainbow, the violet merges into blue, blue into green and so on.

Nucleophiles and electrophiles are reaction intermediates having electron rich and electron deficient centres respectively. Hence, they tend to attack electron deficient and electron rich centres respectively. Classify the following species as electrophiles and nucleophiles.

(a) How many sub-shells are associated with n = 4?
(b) How many electrons will be present in the sub-shells having m_s value of -1/2 for n = 4? (Intermediate)

Predict the major product (s) of the following reactions and explain their formation.