Question 1

The band spectrum is caused by:

Accepted Answer

The band spectrum is caused by molecules. The energy levels of molecules are so close to each other that they combine to form a band. The valence band and conduction band are two types of bands. Electron transition between these two bands form band spectrum.

Question 2

The atomic number at which filling of a g-orbital is likely to begin is:

Accepted Answer

The above question can be answered on the basis of reasoning from analogy. We note that two periods have to pass before d-orbitals begin to fill. This is also true of the spot where f-orbitals commence filling. The second row where f-orbitals fill happens to be row #7 (the one starting with Fr). The first element where 5f-orbitals enter in is actinium (Ac, Z = 89). Adding 32 to this would give element #121 termed as Unbiunium, the first Super-Actinide.

Question 3

The best evidence that electrons are arranged in definite orbits or energy levels is based on the observation that:

Accepted Answer

The best evidence that electrons are arranged in definite orbits or energy levels is based on the observation that the spectral lines of hydrogen atom consist of discrete lines and not continuous bands.

Question 4

Which of the following energy state is filled by an electron after the completion of  4p  orbital?

Accepted Answer

When  4p  orbital in any atom are filled completely, the next electron goes in  5s(n+l=5+0=5)  not in  4d(n+l=4+2=6) ,electron first enters into the subshell which is having less  (n+l)  value (energy). Hence the  5s  is filled first than  4d .

Question 5

If Aufbau rule is violated, then  Ca^{20}   will be in:

Accepted Answer

According to the Aufbau principle, electron enters into the lowest energy level (orbital), before entering into a higher energy level. Hence, according to this principle, the electronic configuration of  Ca^{20}  is  1s^22s^22p^63s^23p^64s^2 , as differentiating electron enters into the s-orbital,  Ca  belongs to s-block. If we don't follow the Aufbau rule, the electronic configuration of  Ca^{20}  would be  1s^22s^22p^63s^23p^63d^2 .Here, the differentiating electron is entering in the d orbital, so it would belong to the d-block element.

Question 6

Which of the following is/are true as per Thomson's model of atom?

Accepted Answer

Thomson's model of atom states that:1. An atom consists of a positively
charged sphere with electrons embedded in it.2. Total positive and negative charges in the atom are equal in magnitude. So, atom is electrically neutral.

Question 7

The aufbau principle is violated in _______.

Accepted Answer

The option A and B are not valid as in option A, 2pz should be filled first, then the second electron will be added in 2px and in option B, filling of 2p orbitals starts only after the complete filling of 2s orbitals as per Aufbau's principle.

Question 8

After completion of ‘ np ’ level, the electron enters into which level according to  (n+p)  rule?

Accepted Answer

Energy of nd level would be higher than  (n+1)s . nd=n+2 ,   (n+1)s=n+1 .So, electron will enter into lower energy level.i.e,  (n+1)s Let us take an example of  '4p'  orbital. As per Moeller diagram, the orbital that will be filled after  '4p'  orbital is  '5s' . Hence,  (n+1)s  orbital will be filled after  'np'  orbital.

Question 9

Which of the following properties are similar for isotopes?

Accepted Answer

Isotopes have same atomic numbers but different mass numbers. This also means that the isotopes have the same number of electrons. Chemical properties are determined by electronic configuration. So, with the same electronic configuration, they have similar chemical properties.

Question 10

To which of the following is Bohr's theory applicable:I)  He^{+}  II)  Li^{2+} III) Tritium  IV)  Be^{2+} The correct combination is:

Accepted Answer

Bohr's atomic model explains the spectra of single-electron atoms like  H -atom. It does not explain the spectra of multi-electron atoms. So the atoms which are isoelectronic and have the same electronic configuration are well explained by this atomic model. He^+ ,  Li^{2+}  and tritium  _{ 1 }{ H }^{ 3 }  have same number of electrons as that of hydrogen atom i.e.  1  while  Be^{2+}  is formed by losing  2e . So, it is a two-electron system.Option D is correct.

Structure Of Atom

Chemistry
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The band spectrum is caused by:

The atomic number at which filling of a g-orbital is likely to begin is:

The best evidence that electrons are arranged in definite orbits or energy levels is based on the observation that:

Which of the following energy state is filled by an electron after the completion of $4 p$ orbital?

If Aufbau rule is violated, then $C a^{20}$ will be in:

Which of the following is/are true as per Thomson's model of atom?

The aufbau principle is violated in _______.

After completion of ‘ $n p$ ’ level, the electron enters into which level according to $(n + p)$ rule?

Which of the following properties are similar for isotopes?

To which of the following is Bohr's theory applicable:
I) $H e^{+}$
II) $L i^{2 +}$
III) Tritium
IV) $B e^{2 +}$
The correct combination is:

Structure Of Atom

Chemistry 1062 Views

The band spectrum is caused by:

The atomic number at which filling of a g-orbital is likely to begin is:

The best evidence that electrons are arranged in definite orbits or energy levels is based on the observation that:

Which of the following energy state is filled by an electron after the completion of 4p orbital?

If Aufbau rule is violated, then Ca20 will be in:

Which of the following is/are true as per Thomson's model of atom?

The aufbau principle is violated in _______.

After completion of ‘np’ level, the electron enters into which level according to (n+p) rule?

Which of the following properties are similar for isotopes?

To which of the following is Bohr's theory applicable: I) He+ II) Li2+ III) Tritium IV) Be2+ The correct combination is:

Chemistry
1062 Views

Which of the following energy state is filled by an electron after the completion of $4 p$ orbital?

If Aufbau rule is violated, then $C a^{20}$ will be in:

After completion of ‘ $n p$ ’ level, the electron enters into which level according to $(n + p)$ rule?

To which of the following is Bohr's theory applicable:
I) $H e^{+}$
II) $L i^{2 +}$
III) Tritium
IV) $B e^{2 +}$
The correct combination is: