1

### IIT-JEE 1988

The outermost electronic configuration of the most electronegative element is
A
ns2 np3
B
ns2 np4
C
ns2 np5
D
ns2 np6
2

### IIT-JEE 1988

The wavelength of a spectral line for an electronic transition is inversely related to :
A
The number of electrons undergoing the trasition
B
The nuclear charge of the atom
C
the difference in the energy of the energy levels involved in the transition
D
the velocity of the electron undergoing the transition
3

### IIT-JEE 1988

The triad of nuclei that is isotonic is
A
${}_6^{14}C$, ${}_7^{15}N$, ${}_9^{17}C$
B
${}_6^{12}C$, ${}_7^{14}N$, ${}_9^{19}C$
C
${}_6^{14}C$, ${}_7^{14}N$, ${}_9^{17}C$
D
${}_6^{14}C$, ${}_7^{14}N$, ${}_9^{19}C$
4

### IIT-JEE 1986

The ratio of the energy of a photon of 2000Å wavelength to that 4000Å radiation is
A
1/4
B
4
C
1/2
D
2