CBSE - Class 11 Chemistry Structure of Atom Worksheet
1.
Indicate the number of unpaired electrons in : (c) Cr,
2.
A photon of wavelength $4 \times 10^{-7}$ m strikes on metal surface, the work function of the metal being 2.13 eV. Calculate (ii) the kinetic energy of the emission, (1 eV= $1.6020 \times 10^{-19}$ J).
3.
(iii) Which atoms are indicated by the following configurations ? (a) [He] $2s^1$
4.
If the diameter of a carbon atom is 0.15 nm, calculate the number of carbon atoms which can be placed side by side in a straight line across length of scale of length 20 cm long.
5.
How much energy is required to ionise a H atom if the electron occupies $n$ = 5 orbit? Compare your answer with the ionization enthalpy of H atom (energy required to remove the electron from $n$ =1 orbit).
6.
Using s, p, d notations, describe the orbital with the following quantum numbers. (b) $n = 3; l=1$
7.
Following results are observed when sodium metal is irradiated with different wavelengths. Calculate (a) threshold wavelength and, (b) Planck’s constant. $\lambda$ (nm) 500 450 400, $v \times 10^{-5}$ (cm s$^{-1}$) 2.55 4.35 5.35
8.
Neon gas is generally used in the sign boards. If it emits strongly at 616 nm, calculate (a) the frequency of emission, (b) distance traveled by this radiation in 30 s (c) energy of quantum and (d) number of quanta present if it produces 2 J of energy.
9.
Indicate the number of unpaired electrons in : (b) Si,
10.
(i) Calculate the total number of electrons present in one mole of methane.
11.
What is the lowest value of $n$ that allows $g$ orbitals to exist?
12.
Explain, giving reasons, which of the following sets of quantum numbers are not possible. (f) $n$ = 3, $l$ = 1, $m_l$ = 0, $m_s$ = + $\frac{1}{2}$
13.
The electron energy in hydrogen atom is given by $E_n = (–2.18 \times 10^{-18})/n^2$ J. Calculate the energy required to remove an electron completely from the $n$ = 2 orbit. What is the longest wavelength of light in cm that can be used to cause this transition?
14.
Using s, p, d notations, describe the orbital with the following quantum numbers. (c) $n = 4; l =2$;
15.
The work function for caesium atom is 1.9 eV. Calculate (a) the threshold wavelength and (b) the threshold frequency of the radiation. If the caesium element is irradiated with a wavelength 500 nm, calculate the kinetic energy and the velocity of the ejected photoelectron.
16.
In astronomical observations, signals observed from the distant stars are generally weak. If the photon detector receives a total of $3.15 \times 10^{-18}$ J from the radiations of 600 nm, calculate the number of photons received by the detector.
17.
Calculate the wavelength of an electron moving with a velocity of $2.05 \times 10^7$ m s$^{-1}$.
18.
(iii) Which atoms are indicated by the following configurations ? (c) [Ar] $4s^2 3d^1$.
19.
Using s, p, d notations, describe the orbital with the following quantum numbers. (d) $n=4; l=3$.
20.
An atom of an element contains 29 electrons and 35 neutrons. Deduce (ii) the electronic configuration of the element.
