MCQs (One or More Correct Option): Structure of Atom | JEE Advanced - Free

have same number of neutrons

(= A – Z) as 

Because they have isotopes with different masses.
The average atomic mass is the weighed mean of their presence in nature; eg. Cl³⁵ and Cl³⁷ are present in ratio 3 : 1 in nature.

So  

α -particles pass through because most part of the atom is empty.

In tritium (the isotope of hydrogen) nucleus there is one proton and 2 neutrons.

∴ n + p = 3. In deuterium nucleus there is one proton and one neutron

∴ n + p = 2.

The energy of an electron on Bohr orbits of hydrogen atoms is given by the expression

Where n takes only integral values. For the first Bohr orbit, n = 1 and it is given that E₁ = –13.6 eV

Hence of the given values of energy,, only – 3.4 eV and – 1.5 eV can be obtained by substituting n =2 and 3 respectively in the above expression.

(a) ₂₄Cr = 1s², 2s²2p⁶, 3s²3p⁶3d⁵, 4s¹ = [Ar] 3d⁵,4s¹
(b) For magnetic quantum number (m), negative values are possible.
For s - subshell, l  = 0, hence m = 0 for p - subshell, l = 1, hence m = –1, 0, +1
(c) ₄₇Ag = 1s², 2s² 2p⁶, 3s²3p⁶3d¹⁰, 4s² 4p⁶ 4d¹⁰,5s¹
Hence 23 electrons have a spin of one type and 24 of the opposite type.
(d) Oxidation state of N in HN₃ is –1/3.

 (a)   (α - emission) ;

(b)(β - emission);

(c)(positron - emission);

(d)  (electron - capture)

Atomic number increases during β-emission

According to Hund's rule pairing of electrons starts only when each of the orbital in a sub shell has one electron each of parallel spin.

∴ (a) and (d) are correct ground state electronic configurations of nitrogen atom in ground state.