Home
Class 12
CHEMISTRY
Assertion: The third period contains onl...

Assertion: The third period contains only 8 electrons and not 18 like 4th period.
Reason: In III perriod filling starts from `3s^(1)` and complete at `3p^(6)` whereas in IV period it starts from `4s^(1)` annd complete after `3d^(10)` and `4s^(2)`.

A

If both assertion and reason are true annd the reason is the correct explanation of assertion

B

If both assertion and reason are true but reason is not the correct explanation of assertion

C

If assertion is true but the reason is false

D

if assertion is false but the reason is true

Text Solution

Verified by Experts

The correct Answer is:
A
Promotional Banner

Topper's Solved these Questions

  • PERIODIC PROPERTIES

    VK JAISWAL|Exercise MATCH THE COLUMN|13 Videos

  • p-BLOCK ELEMENTS

    VK JAISWAL|Exercise SUBJECTIVE PROBLEMS|36 Videos

  • QUALITATIVE INORGANIC ANALYSIS

    VK JAISWAL|Exercise SUBJECTIVE PROBLEMS|5 Videos

Similar Questions

Explore conceptually related problems

The period of revolution of the electron in the third orbit in a hydrogen atom is 4.132 xx 10^(-15) s . Hence find the period in the 5th Bohr orbit.

Assertion : The outer electronic configuration of Cr and Cu are 3d^(5) 4s^(1) and 3d^(10) 4s^(1) respectively . Reason : Electrons are filled in orbitals in order of increasing energies given by (n+l) rule.

A particle executes SHM with a time period of 2s and amplitude 10 cm . Find its (i) Displacement (ii) Velocity (iii) Acceleration after 1/6 s, Starting from mean position.

A particle is executing simple harmonic motion with an amplitude of 10 cm and time period of 4s. Calculate its displacement, velocity and acceleration after 1/2 seconds, starting from the mean position.

This time period of a particle undergoing SHM is 16 s. It starts motion from the mean position. After 2 s, its velocity is 0.4 ms^(-1) . The amplitude is

Numerous forms of the periodic table have been revised from time to time. A modern verion, which is most convenient and widely used is the long or extended from the periodic table. The aufbau principle (electrons are filled in the progressive order of their increasing energy i.e., by n + l rule) and the electronic configuration of atom provides a theoretical foundation for the periodic classification. The horizontal rows are called periods. There are altogether seven periods. The first period consists of 2 elements. The subsequent periods consist of 8, 8, 18 and 32 elements respectively. The seventh maximum of 32 elements. Elements having similar outer electronic configurations in their atoms are grouped in vertical columns. These are referred to as groups or famillies. According to the recommendation of IUPAC, the groups are numbered 1 to 18 replacing the older notation of groups 0, IA, IIA ..... VIIA, VIII, IB, ...... VII B. Each successive period in the periodic table is associated with the filling up of next higher principal energy level following aufbua sequence. The number of elements in each period is twice the number of atomic orbitals avaliable in the energy level that is being filled. All the elements are classified into four blocks, i.e., s-block, p-block, d-block and f-block depending on the type of atomic orbitals that are being filled with the last electron of the element. Elements a,b,c,d and e have the following electronic configurations. (a) 1s^(2),2s^(2)2p^(1) (b) 1s^(2),2s^(2)2p^)(6),3s^(2)3p^(1) (c) 1s^(2),2s^(2)2p^(6),3s^(2)3p^(1) (d) 1s^(2),2s^(2)2p^(6),3s^(2)3p^(5) (e) 1s^(2), 2s^(2)2p^(6),3s^(2)3p^(5) Which among these will belong to the same group in periodic table?

The period of oscillation of a particle in SHM is 4s and its amplitude of vibration is 4cm . The distance of the particle (1)/(3)s after passing the mean poistion is

VK JAISWAL-PERIODIC PROPERTIES-ASSERTION-REASON TYPE QUESTIONS
  1. Assertion: The formation of F((g))^(-) from F((g)) is exothermic, wher...

    Text Solution

    |

  2. Statement-1: Na^(+) and AI^(3+) are isoelectronic but the magnitude of...

    Text Solution

    |

  3. Assertion: The third period contains only 8 electrons and not 18 like ...

    Text Solution

    |

  4. Statement-I : Cs and F combines violently to form CsF. Statement-II :...

    Text Solution

    |

  5. Statement-1: Second electron gain enthalpy of halogens is always posit...

    Text Solution

    |

  6. Assertion: F atom has less electron afffinity than Cl atom. Reason: ...

    Text Solution

    |

  7. Assertion: Among the halogens bond energy of F(2) is minimum. Reason...

    Text Solution

    |

  8. Assertion: The first ionization energy of Be is greater than that of B...

    Text Solution

    |

  9. Assertion : Noble gases have highest ionisation enthalpies in their re...

    Text Solution

    |

  10. Assertion: Helium and beryllium have similar outer electronic configur...

    Text Solution

    |

  11. Assertion: The first ionisation enthalpy of aluminium is lower than th...

    Text Solution

    |

  12. Assertion: In CsF, salt, size of Cs^(+) is slight higher than size of ...

    Text Solution

    |

  13. Assertion: First electron affinity of all elements is positive. Reas...

    Text Solution

    |

  14. Assertion: helium atom has highest ionisation energy among all the ele...

    Text Solution

    |

  15. Assertion: F^(-) ion has highest hydrated radius among the other halid...

    Text Solution

    |

  16. Assertion: magnitude of electron gain enthalpy of oxygen is less than ...

    Text Solution

    |

  17. Assertion: Formation of Cl^(-) ion is exothermic wheres O^(2-) ion for...

    Text Solution

    |

  18. Assertion: The electron gain enthalpy of N is +ve while that of P is -...

    Text Solution

    |

  19. Assertion: The formation of F((g))^(-) from F((g)) is exothermic, wher...

    Text Solution

    |

  20. Assertion: Na^(+) and Al^(3+) are isoelectronic but ionic radius Al^3+...

    Text Solution

    |