CBSE
The radius of hydrogen atom is 0.53 Å. The radius of 3Li2+ is of:
1.27 Å
0.17 Å
0.57 Å
0.99 Å
If a species has 16 protons, 18 electrons and 16 neutrons, find the species and its charge.
S1-
Si2-
P3-
S2-
are respectively
4,1
3,7
8,1
4,7
The orbital angular momentum of an electron in 2s orbital is
zero
For the Paschen series the values of n1 and n2 in the expression
n1= 1, n2 = 2, 3, 4, ...
n1= 2, n2 = 3, 4, 5,...
n1= 3, n2 = 4,5,6,...
n1= 4, n2 = 5,6,7,...
A radioactive atom emits two particles and one particle successively. The number of neutrons in the nucleus of the product will be:
X - 4 - Y
X - Y - 5
X - Y - 3
X - Y - 6
In Sommerfeld's modification of Bohr's theory, the trajectory of an electron in a hydrogen atom is
a perfect ellipse
a closed ellipse-like curve, narrower at the perihelion position and flatter at the aphelion position
a closed loop on spherical surface
a rosette
Which of the following expressions gives the de-Broglie relationship?
1 mole of photon, each of frequency 2500 s-1, would have approximately a total energy of
10 erg
1 J
1 eV
1 MeV
The number of electron and neturons of an element is 18 and 20 respectively. Its mass number is
2
17
37
38