1

### IIT-JEE 2005 Screening

The number of radial nodes of 3s and 2p orbitals are respectively
A
2, 0
B
0, 2
C
1, 2
D
2, 1
2

### IIT-JEE 2004 Screening

The radius of which of the following orbit is same as that of the first Bohr's orbit of hydrogen atom?
A
He+ (n = 2)
B
Li2+ (n = 2)
C
Li2+ (n = 3)
D
Be3+ (n = 2)
3

### IIT-JEE 2002 Screening

If the nitrogen atom has electronic configuration 1s7, it would have energy lower than that of the normal ground state configuration 1s22s22p3, because the electrons would be closer to the nucleus. Yet 1s7 is not observed because it violates
A
Heisenberg uncertainty principle
B
Hund's rule
C
Pauli exclusion principle
D
Bohr postulate of stationary orbits
4

### IIT-JEE 2002 Screening

Rutherford's experiment, which established the nuclear model of the atom, used a beam of
A
$\beta-particles$, which impinged on a metal foil and got absorbed
B
$\gamma-particles$, which impinged on a metal foil and ejected electrons
C
helium atoms, which impinged on a metal foil and got scattered
D
helium nuclei, which impinged on a metal foil and got scattered