Question 2 :
The salt of an oxyacid of a metal $M$ contains one sulphur and four oxygen atoms. The oxyacid of the salt is:
Question 3 :
In 1913, Bohr proposed his quantized shell model of the atom to explain :
Question 4 :
Who suggested the distribution of electrons into different orbits of an atom?
Question 7 :
An atom or group of atoms of the same or of different elements that behaves as a single unit with a positive or negative charge is known as :
Question 9 :
Isotopes of cobalt .......... is used in the treatment of cancer.
Question 12 :
Radius of the nucleus is about ............. times less than the radius of the atom.<br/>
Question 13 :
The presence of nucleus in an atom is determined by Rutherford $\alpha - ray$ scattering experiment.<br/>
Question 14 :
The position of .......... could not be explained in the plum pudding model.
Question 17 :
According to postulates of Bohr's atomic model, the electrons in atom move round the nucleus :
Question 18 :
Valency can be defined as the same number of hydrogen atoms or double the number of oxygen atoms that element combines with.
Question 19 :
Isotopes of iodine _______ is used in the treatment of goiter.
Question 20 :
According to Rutherford, the electron revolves around the nucleus in definite orbits but :
Question 21 :
Bohr modified the ___________ by adding that the electrons move in orbits of fixed size and energy.
Question 22 :
Total no. of electrons present in $48$ g of $Mg^{2+}$ are:
Question 24 :
A sample of carbon atoms is found to contain atoms that have mass numbers of $12$, $13$ and $14$. Which statement best describes how this is possible?
Question 25 :
It was found that electrons have negligible mass but have one unit of negative charge. Which of the following model satisfies this statement?
Question 27 :
While revolving in discrete orbits the electrons do not radiate energy. These orbits or shells are called .................. 
Question 30 :
Goldsteins experiments which involved passing high voltage electricity through gases at very low pressureresulted in the discovery of:
Question 31 :
On moving horizontally across 2nd period, the number of electrons in the outermost shell increases from :
Question 32 :
The fundamental particle(s) not present in the nucleus of hydrogen atom is :
Question 33 :
The number of electrons and neutrons of an element is $18$ and $20$ respectively. its mass number is :
Question 35 :
Which of the following are correct about the subatomic particles found in $\displaystyle ^{ 37 }{ { Cl }^{ - } }$?<br/>i.  21 neutrons<br/>ii. 17 protons<br/>iii. 16 electrons
Question 36 :
Three molecules X, Y and Z have a contracted octet, an octet and an expanded octet. Identity them.
Question 37 :
Which experiment was developed on the plum pudding model of the atom?
Question 39 :
Two isotopes of an elements $Q$ are ${ Q }^{ 97 }$ (23.4% abundance) and ${ Q }^{ 94 }$ (76.6% abundance). ${ Q }^{ 97 }$ is $8.082$ times heavier than ${ C }^{ 12 }$ and ${ Q }^{ 94 }$ is $7.833$ times heavier than is ${ C }^{ 12 }$. What is the average atomic weight of the elements $Q$?
Question 43 :
One species of element $X$ has an atomic number of $9$ and a mass number of $19$; one species of element $Y$ has an atomic number of $10$ and a mass number of $19$. Which of the following statements about these two species is true?
Question 45 :
Maximum number of electrons that can be filled in the third orbit of an atom is :
Question 50 :
Calculate number of neutrons present in $12 \times 10^{25}$ atoms of oxygen $(_8O^{17})$: <br>(Given : N$_A = 6 \times 10^{23}$)
Question 51 :
If an electron revolving in $n^{th}$ excited state orbit with $1090\ km/s$ in $Li^{+2}$ ion then find max find max possible spectral lines for the electron transition from the same excited state to find excited state.
Question 53 :
Statement 1: The value of Avogadro's constant is $6.022\times {10}^{23}$<br/>Statement 2: Mole is the ratio of number of atoms present in the substance to the Avogadro number.<br/>Now choose the correct option :
Question 54 :
The radius of which of the following orbit is same as that of the first Bohr's orbit of hydrogen atom?
Question 55 :
A potential difference of $V$ volts is applied on an $\alpha$-particle at rest in order to get sufficient velocity so that when it is projected from infinity towards $Au$ foil, it can reach closest upto $x$ meters from $Au$ nucleus. If instead of an $\alpha$-particle, a proton is used in the above experiment and is accelerated from rest by the same potential difference, then the closest distance from the $Au$ nucleus upto which it can reach is $y$ meters. The ratio $x : y$ is _______.<br/>
Question 56 :
If one were to apply Bohr's model to a particle of mass 'm' and charge 'q' moving in a plane under the influence of a magnetic field 'B', the energy of the charged particles in the $n^{th}$ level will be:
Question 57 :
The oxidation state of Barium in $Ba({ H }_{ 2 }{ PO }_{ 2 }{ ) }_{ 2 }$  is:
Question 58 :
If $r_0$ be the radius of first Bohr's orbit of $H-$atom, then the de-Broglie's wavelength of an electron revolving in the third Bohr's orbit will be:
Question 60 :
When a gold sheet is bombarded by a beam of $\alpha$-particles, only a few of them get deflected whereas most go straight, undeflected because:<br/>
Question 61 :
The motion of a particle along a straight line is described by equation $x= 8 + 12t - { t }^{ 3 }$ where, $x$ is in metre and $t$ in sec. The retardation of the particle when its velocity becomes zero is :
Question 62 :
The formation of the oxide ion, O$^{2-}_{(g)}$, from oxygen atom requires first an exothermic and then an endothermic step as shown below:<br/>$O_{(g)} + e^{-} \rightarrow O^{-}_{(g)}; \Delta H^{\circ} = -141 kJ mol^{-1}$<br/>$O_{(g)}^{-} + e^{-} \rightarrow O^{2-}_{(g)}; \Delta H^{\circ} = +780 kJ mol^{-1}$<br/>Thus, process of formation of $O^{2-}$ in gas phase is unfavourable even though $O^{2-}$ is isoelectronic with neon. It is due to the fact that:
Question 63 :
Neutron does not get deflected in the presence of electric field.
Question 64 :
The radius of the fourth orbit of an atom is 0.64 nm. The radius of the 3rd orbit of the atom is:
Question 65 :
Assertion: $\displaystyle BeCl_{2}$ can not be easily hydrolysed.
Reason: $\displaystyle BeCl_{2}$ is electron deficient compound.
Question 66 :
In Millikan's oil drop experiment, the charge of three oil drops X, Y, and Z have been found to be 2, 0.04 and 0.8 respectively. What could be the probable charge of an electron and the number of electrons attached to these oil drops?
Question 67 :
Total number of electrons present in 48g $<br/>{\text{Mg}}^{{\text{ 2+}}} <br/>$ are:<br/>
Question 68 :
Multiple Answer Question <br/>According to Bohr, when electron jumps from one shell to another:
Question 69 :
Which other element has the same number of valence electrons as aluminum?
Question 70 :
The ratio of the difference in energy between the first and second Bohr orbit to that between the second and third Bohr orbit is:
