An atom having atomic mass number 13 has 7 neutrons. What is the atomic number of the atom?

The arrangement of orbitals on the basis of energy is based upon their (n+l ) value. Lower the value of (n+l ), lower is the energy. For orbitals having same values of (n+l), the orbital with a lower value of n will have lower energy.

I. Based upon the above information, arrange the following orbitals in the increasing order of energy

(a) 1s, 2s, 3s, 2p

(b) 4s, 3s, 3p, 4d

(c) 5p, 4d, 5d, 4f, 6s

(d) 5f, 6d, 7s, 7p

II. Based upon the above information, solve the questions given below :

(a) Which of the following orbitals has the lowest energy?

4d, 4f, 5s, 5p

(b) Which of the following orbitals has the highest energy?

5p, 5d, 5f, 6s, 6p

Which of the following will not show deflection from the path on passing through an electric field?

Proton, cathode rays, electron, neutron

Wavelengths of different radiations are given below :

λ(A) = 300 nm

λ(B) = 300 μm

λ(c) = 3 nm

λ (D) 30 A°

Arrange these radiations in the increasing order of their energies.

The electronic configuration of the valence shell of Cu is 3d104s1 and not 3d94s2. How is this configuration explained?