Test: Structure of Atom - 1 - NEET MCQ

The wavelength λ is inversely proportional to the square root of kinetic energy. So if KE is increased 4 times, the wavelength becomes half.

λ∝1/√KE

Hence Option A is the answer.

Given m_p = 1.67×10^-27kg
h = 6.63×10^-34Js
v = 1.0×10³ms-1

We know wavelength λ = h/mv
∴λ = 6.63×10^-34/(1.67×10^-27 × 1.0×10³)
= 0.40×10^-10
≈ 0.40nm

Hence, Option (B) is the Correct Answer.

Correct Answer is A.

Number of orbitals in a shell = n² = (5)² = 25

Bohr Model of atom:

• An atom is made up of three particles: Electrons, neutrons and protons.
• The protons and neutrons are located in a small nucleus at the centre of the atom.
• The electrons revolve rapidly around the nucleus at the centre of the atom.
• There is a limit to the number of electrons that each energy level can hold.
• Each energy level is associated with a fixed amount of energy.
• There is no change in the energy of electrons as long as they keep revolving in the same energy level.

Bohr explained the stability through the concept of revolution of electrons in different energy levels.

The change in the energy of an electron occurs when it jumps from lower to higher energy levels. When it gains energy, it excites from lower to higher and vice versa.
Thus energy is not lost and the atom remains stable.

• Number of radial nodes = n - l – 1

where n = principal quantum number, l = azimuthal quantum number

• For 3p orbital, n = 3 – 1 – 1 = 1
• Number of radial nodes = 3 – 1 – 1 = 1. 

n = 6, l = 2 means 6d → will have 5 orbitals. 

∴ max 10 electrons can be accommodate as each orbital can have maximum of 2 electrons. 

• An atom consists of a positively charged sphere with electrons filled into it. The negative and positive charges present inside an atom are equal and as a whole, an atom is electrically neutral.
• Thomson’s model of the atom as compared to plum pudding and watermelon.
• He compared the red edible part of the watermelon to a positively charged sphere whereas the seeds of watermelon to negatively charged particles.

• Concept of electrons moving in a circular path of fixed energy called orbits was put forward by Bohr and not derived from Rutherford's scattering experiment.
• Out of a large number of circular orbits theoretically possible around the nucleus.
• The electron revolves only in those orbits which have a tired value of energy Hence, these orbits are called energy level or stationary states.

The charge on electrons was determined by Milliken by using an oil drop experiment.

• The nature of positive rays produced in a vacuum discharge tube depends upon the nature of the gas-filled.
• The positive rays consist of positive ions obtained by removing one or more electrons from gas molecules.

• Tritium (³H) is the only radioactive isotope of hydrogen.
• The nucleus of a tritium atom consists of a proton and two neutrons.

= 4000/2000
= 2

Isoelectronic species are the having same number of electrons.
Number of electrons in CO = 6 + 8 = 14
O₂^- = 16 + 1 = 17
N₂⁺ = 14 - 1 = 13
O₂⁺ = 1 6 - 1 = 15
CN^- = 6 + 7 + 1 = 14
Hence, CO isoelectronic with CN⁻ ion.