11.

The orbital angular momentum of an electron in 2s orbital is

• $+\frac{1}{2}\frac{\mathrm{h}}{2\mathrm{\pi }}$

• zero

• $\frac{\mathrm{h}}{2\mathrm{\pi }}$

• $\sqrt{2}\frac{\mathrm{h}}{2\mathrm{\pi }}$

The ionisation energy of hydrogen atom is 13.6eV. What will be the ionisation energy of He⁺?

• 13.6 eV

• 54.4 eV

• 122.4 eV

• Zero

The number of electron and neturons of an element is 18 and 20 respectively. Its mass number is

• 2

• 17

• 37

• 38

$\mathrm{The} \mathrm{number} \mathrm{of} \mathrm{\alpha } \mathrm{and} \mathrm{\beta } \mathrm{particles} \mathrm{emitted} \mathrm{in} \mathrm{nuclear} \mathrm{reaction} {}_{90}\mathrm{Th}^{228}\to {}_{83}\mathrm{Bi}^{212}$ are respectively

• 4,1

• 3,7

• 8,1

• 4,7

2g of mixture of CO and CO₂ on reaction with excess I₂O₅ produced 2.54g of I₂. What would be the mass% of CO₂ in the original mixture?

• 60

• 30

• 70

• 35

When 10g of 90% pure lime stone is heated completely, the volume (in litres) of CO₂ is liberated at STP is

• 22.4

• 2.24

• 20.16

• 2.016

Which element has highest electronegativity ?

• F

• He

• Ne

• Na

The correct order of radii is

• N <Be <B

• F^-<O^2-<N^3-

• Na< Li< K

• Fe³⁺< Fe²⁺< Fe⁴⁺

Law of constant composition is same as the law of

• conservation of mass

• conservation of energy

• multiple proportion

• definite proportion

BCl₃ is a planar molecule, while NCl₃ is pyramidal, because

• N-Cl bond is more covalent than B-Cl bond

• nitrogen atom is smaller than boron atom

• B-Cl bond is more polar than NCl bond

• BCl₃ has no lone pair of electrons but NCl₃ has a lone pair of electrons.