Recent questions tagged structure-of-atom

Description : What is Aufbau’s principle? How it helps to fill electrons in an atom in different orbitals?

Last Answer : Ans Electrons are filled in orbitals of an atom according to increasing energies which is in accordance to (n+l) values of electrons. If (n+l )values are same the electron goes to orbital having lower value of n.

Description : What do you mean by Pauli’e exclusive principle? What is its significance?

Last Answer : Ans No two electrons will have same set of all q.no. If n,l,m are same i.e. same orbital ‘s’ will be differ. It shows that all electrons have a definite place in an atom or their own identity.

Description : What is Hund’s rule of maximum multiplicity? What is its significance?

Last Answer : Ans Pairing of electrons in an orbital takes place only when all orbitals of same sub-shell become singly occupied. It helps to equalize energy of a sub-shell

Description : Explain the significance of spin quantum number.

Last Answer : Ans.The direction of spinning of an electron in an orbit as well as the net magnetic moment of an orbital.

Description : Tell what would happen to the stability of an atom, with atomic number higher than18, if the aufbau principle was not introduced.

Last Answer : Ans. We cannot find out the exact reason of stability of an atom & why they should have filled inner orbits before outermost shell.

Description : Explain why half-filled orbitals have extra stability.

Last Answer : Ans. It has symmetrical electron density as well as greater exchange energy.

Description : How many of the following are possible: 1p, 2s, 3p, 3f, 3d.

Last Answer : Ans.2s , 3p & 3d are possible.

Description : Explain the significance of Azimuthal quantum number.

Last Answer : Ans. It refers as sub-energy level of an atom.

Description : How many quantum numbers are needed to designate an orbital?

Last Answer : Ans.Three quantum numbers.

Description : What accounts for the stability of an electron in multi-electron atom?

Last Answer : Ans. i.The angular momentum of an electron is integral multiple of h/2ח ii. The symmetrical electron density of an orbit. iii.The maximum transition energy of an orbital.

Description : Is the energy of an electron in 2s orbital same as of that in 2p orbital? Why?

Last Answer : Ans. No, the energy depends upon (n+l) values in an atom. Hence 2p orbital has greater energy than 2s.

Description : “In reality all the s-orbitals are spherically symmetric.” What does this represent?

Last Answer : Ans. The probable density of an electron in s-orbital is equally distributed at all coordinates in space.

Description : Why is s-orbital orbital considered non directional while p-orbital directional?

Last Answer : Ans. Electron density in s-orbital is equal in all direction while it dumble shaped along one axis in p- orbitals.

Description : Find the number of radial and angular nodes in 3d subshell?

Last Answer : Ans. Zero-angular node as well as radial nodes.

Description : How many maximum 3s electrons can have magnetic spin quantum number -1/2?

Last Answer : Ans. 1 electrons.

Description : What are different types of quantum numbers , write them with their symbols ?

Last Answer : Ans. 1.Principal Quantum Numbers (n) 2.Azimuthal Quantum Numbers(l) 3.Magnetic Quantum Numbers (m) 4.Spin Quantum Numbers(s)

Description : Define Pauli’s exclusion principle ?

Last Answer : Ans. No two electrons in an atom can have same set ofall four quantum numbers. If three are same one Quantum number must have different value.

Description : Give the points of Rutherford Model.

Last Answer : Ans. 1. Atom is neutral. 2.Whole mass is concentrated in nucleus. 3.Electrons are revolving in orbits.

Description : Write two properties which cannot be explain by wave nature of radiation

Last Answer : Ans. 1.Photo electric effect 2. Black Body radiation

Description : Write the draw back of Rutherford Atomic Model.

Last Answer : Ans (1). He was unable to explain the stability of Atom. (2). He could not explain the line spectrum.

Description : Why; e/m value is not constant for canal rays ?

Last Answer : Ans. Mass of particles of cathode rays is not constant.

Description : What is threshold frequency?

Last Answer : Ans –The minimum frequency required to eject out electron from an atom.

Description : Name the spectral series which appear in the region of electromagnetic spectrum. (a) Visible region (b) UV region (c) Far IR region

Last Answer : Ans: (a) Balmer Series (b) Lymen Series (c) Pfund Series

Description : What is the difference between Quantum and photon?

Last Answer : Ans. The smallest packet of Energy of any radiation is called as Quantum and that of Light is known as Photon.

Description : State Heisenberg Uncertainty Principle.

Last Answer : Ans. It is impossible to determine the exact position & exact momentum or velocity of microscopic particle.