Structure of Atoms

This is a Short Answer Type Questions as classified in NCERT Exemplar

Ans: The line spectrum associated with any element possesses lines corresponding to specific wavelengths and these lines are obtained as a result of electronic transitions between the energy levels. Hence, the electrons in these levels have fixed energy i.e., quantized values.

This is a Short Answer Type Questions as classified in NCERT Exemplar

Ans: As per de Broglie, every object in motion has a wave character i.e. every object/matter have dual nature both particle and wave nature. But the wavelengths associated with ordinary objects are so short (because of their large masses) that their wave properties cannot be detected.

Given, m (mass) = 100g, v=100km/hr

 We have

λ = h/mv= 238.5 * 10-³⁴ m

As the wavelength associated with the cricket ball is so small that it can't be detected.

This is a Short Answer Type Questions as classified in NCERT Exemplar

Ans: We have V = 109677 [1/ni ² - 1/nf ² ] cm^-1

 Given, n_i = 2, n_f=4

V =109677 [1/4 - 1/16] = 20564.44 cm^-1

This is a Short Answer Type Questions as classified in NCERT Exemplar

Ans: As per the Hund's rule the half filled and fully filled orbital leads to the extra stability due to the symmetry thus fully filled 3d and half filled 4s is preferred.

This is a Short Answer Type Questions as classified in NCERT Exemplar

Ans:  

We know that energy is inversely proportional to the wavelength

Thus, the increasing order of energy is B

This is a Short Answer Type Questions as classified in NCERT Exemplar

Ans: The mass number (A) is defined as the sum of the number of protons and neutrons present in the nucleus and the atomic number is defined as the number of protons or electrons present in an atom. Thus A=13, the number of neutrons is 7 so the number of protons is 6. Thus, the atomic number is 6.

This is a Short Answer Type Questions as classified in NCERT Exemplar

Ans: The charged particles get deflected by the electric field. As among the given option only neutron is the particle that is neutral thus it does not get deflected by the electric field.

This is a Short Answer Type Questions as classified in NCERT Exemplar

Ans: The number of radial nodes is given by n-l-1, where n is principal quantum number, l is azimuthal quantum number. The number of angular nodes is given by n-l, where n is principal quantum number, l is azimuthal quantum number. Here n =3 and l =1 Thus, angular nodes = 3-1 = 2 and radial node = 3-1-1 = 1.

This is a Short Answer Type Questions as classified in NCERT Exemplar

Ans: In a multielectron atomic system the energy of an electron depends not only on its principal quantum number (shell), but also on its azimuthal quantum number (subshell). Electrons having the same shells and same subshells have the same energy and they are known as degenerate orbitals.

Thus 3d_xy ,3dz² , 3d_yz and 4d_xy, 4d_yz, 4dz² are degenerate.