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Chemistry · Structure of atom

हिन्दी

According to the \( (n + l) \) rule, which of the following subshell pairs has the lower energy and gets filled first?

  1. 4s (\( n+l = 4 \)) and 3p (\( n+l = 4 \))
  2. 4p (\( n+l = 5 \)) and 3d (\( n+l = 5 \))
  3. 3p (\( n+l = 4 \)) and 4s (\( n+l = 4 \))
  4. 3d (\( n+l = 5 \)) and 4s (\( n+l = 4 \))

Correct answer · Option 4

3d (\( n+l = 5 \)) and 4s (\( n+l = 4 \))

Explanation

Subshell with lower \( (n+l) \) value has lower energy. For 4s, \( n+l = 4+0 = 4 \); for 3d, \( n+l = 3+2 = 5 \). Hence 1s fills before 3d.

Related questions

Consider the following statements about quantum rules and orbitals:\n(A) The principal quantum number \( n \) defines the main shell and size of the orbital.\n(B) For a given value of \( n \), there are \( n \) allowed values of \( l \).\n(C) The number of \( m_l \) values for a given \( l \) is \( 2l + 1 \).\n(D) The total number of electrons in a given subshell is \( 2l + 1 \). \nWhich of the above statements are correct?→Given below are two statements:\n Statement I: The 4s orbital has a lower \( (n + l) \) value than the 3d orbital, hence 4s fills before 3d.\n Statement II: Valence electrons are those electrons added to the electronic shell with the lowest principal quantum number. \nIn the light of the above statements, choose the most appropriate answer from the options given below:→If the radius of a nucleus of a heavy atom \( A \) is estimated, what is the approximate ratio of the nuclear radius to the radius of its atom if the atomic radius is of the order of \( 10^{-10}\text{ m} \) and nuclear radius is \( 10^{-14}\text{ m} \)?→What is the energy associated with the first orbit in the hydrogen atom given by \( E_1 = -2.18 \times 10^{-18} \text{ J atom}^{-1} \)? What is the energy associated with the fifth orbit?→
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