The size of the iso-electronic species \(Cl^-\) , \(Ar\) and \(Ca^{2+}\) is affected by 

 Principal quantum number of valence shell

Azimuthal quantum number of valence shell 

 electron – electron interaction in the outer orbitals 

nuclear charge

The radius of the second Bohr orbit for hydrogen atom is : (Planck's Const. h = 6.6262 × \(10^{-34}\) Js; mass of electron = 9.1091 × \(10^{-31}\) kg; charge of electron e = 1.60210 × \(10^{-19}\) C; permittivity of vacuum \(\epsilon_{o}=8.854185×10^{-12}\,\,kg^{-1}m^{-3}A^{2}\) )

 

4.76 Å

0.529 Å

2.12 Å

1.65 Å

Which one of the following sets of ions represents the collection of isoelectronic species?

K\(\large ^{+}\), Cl\(\large ^{-}\), Mg\(\large ^{2+}\), Sc\(\large ^{3+}\)

Na\(\large ^{+}\), Ca\(\large ^{2+}\), Sc\(\large ^{3+}\), F\(\large ^{-}\)

K\(\large ^{+}\), Ca\(\large ^{2+}\), Sc\(\large ^{3+}\), Cl \(\large ^{-}\)

Na\(\large ^{+}\), Mg\(\large ^{2+}\), Al\(\large ^{3+}\), Cl \(\large ^{-}\)

The total number of electrons in 18 ml of water (density = 1 g ml\(\large ^{-1}\)) is

6.02 x 10\(\large ^{23}\)

6.02 x 10\(\large ^{25}\)

6.02 x 10\(\large ^{24}\)

6.02 x 18 x 10\(\large ^{23}\)

The kinetic energy of an electron in the second Bohr orbit of a hydrogen atom is [a\(\large _{0}\) is Bohr radius]

\(\large \frac{h^{2}}{4\pi ^{2}ma^{2}_{_{0}}}\)

\(\large \frac{h^{2}}{16\pi ^{2}ma^{2}_{_{0}}}\)

\(\large \frac{h^{2}}{32\pi ^{2}ma^{2}_{_{0}}}\)

\(\large \frac{h^{2}}{64\pi ^{2}ma^{2}_{_{0}}}\)

The correct set of quantum number for the unpaired electrons of chlorine atom is

\(2,1,-1,+\large\frac12\)

\(2,0,0,+\large\frac12\)

\(3,1,1,^+_-\large\frac12\)

\(3,0,0,^+_-\large\frac12\)

The orbital nearest to the nucleus is

4f

5d

4s

7p

The maximum number of electrons that can have principal quantum number, n = 3, and spin quantum number, m =\(\large -\frac{1}{2}\), is

7

8

9

6

Which of the following is the energy of a possible excited state of hydrogen?

+13.6 eV

-6.8 eV

- 3.4 eV

+6.8 eV

The work function (\(\large \phi \)) of some metals is listed below. The number of metals which will show photoelectric effect when light of 300 nm wavelength falls on the metal is

2

3

4

5

A stream of electrons from a heated
filament was passed between two charged
plates kept at a potential difference V esu.
If e and m are charge and mass of an
electron, respectively, then the value of
h/\(\lambda \) (where \(\lambda \) is wavelength associated
with electron wave) is given by :

meV

2meV

\(\sqrt{meV}\)

\(\sqrt{2meV}\)

The statement that is NOT correct is

Angular quantum number signifies the shape of the orbital

Energies of stationary states in hydrogen like atoms is inversely proportional to the square of the principal quantum number

Total number of nodes for 3s orbital is three.

The radius of the first orbit of He+ is half that of the first orbit of hydrogen atom.

The two electrons have the following set of quantum numbers :

P = 3,2,-2,+\(\large \frac{1}{2}\)

Q =3,,0,0,+\(\large \frac{1}{2}\)

Which of the following statement is true ?

P has lesser energy than Q

P and Q have same energy

P and Q represent same electron

P has greater energy than Q

Which one of the following sets of quantum numbers represents the highest energy level in an atom?

\(\large n=3,\; l=0,\; m=0,\; s=+\frac{1}{2}\)

\(\large n=4,\; l=0,\; m=0,\; s=+\frac{1}{2}\)

\(\large n=3,\; l=1,\; m=1,\; s=+\frac{1}{2}\)

\(\large n=3,\; l=2,\; m=-2,\; s=+\frac{1}{2}\)

The correct arrangement for the ions in the increasing order of their radii is

\(\large Na^{+},Cl^{-1},Ca^{+2}\)

\(\large Ca^{+2},K^{+},S^{-2}\)

\(\large CL^{-},F^{-},S^{-2}\)

\(\large Na^{+},Al^{+3},Be^{+2}\)