Structure of atom practice · Mixed difficulty

Which of the following pairs have identical values of e/m?

The correct de Broglie relationship is:

Assertion: Unlike sound waves, electromagnetic waves do not require medium and can move in vacuum.

Reason: The oscillating electric and magnetic fields produced by oscillating charged particles are parallel to each other and both are perpendicular to the direction of propagation of the wave.

S-I: The ${p}_{{x}}$ orbital has maximum electron density along the y axis and its nodal plane is xz plane.

S-II : For a given atom, for all values of $n$, the ${p}$-orbitals have the same shape, but the overall size decreases as '$n$' increases.

S-I: Elements like $Rb, Cs, Tl, In, Ga$ and $Sc$ were discovered when their minerals were analysed by spectroscopic methods.

S-II: The element helium was discovered in the sun by spectroscopic method.

In which one of the following, the number of protons is greater than number of neutrons but number of protons is less than the number of electrons?

The ionisation potential of singly ionised Helium ion is equivalent to

Which of the following electrons is most tightly bound by the nucleus

Statement (S): H-atom has only one electron in its orbit, but several spectral lines are noticed

Explanation (E): The $\mathrm{H}$-spectra is observed in $\mathrm{H}_2$ gas

Consider the following statements:

I. The attractive interactions of an electron increases with increase of positive charge $\left(Z_e\right)$ on the nucleus.

II. Due to the presence of electrons in the inner shells, the electrons in the outer shell will not experience the full positive charge of the nucleus $\left(Z_e\right)$.

III. The effect will be lowered due to the partial screening of positive charge on the nucleus by the inner shell electrons.

IV. The net positive charge experienced by the other electrons is known as effective nuclear charge $\left(Z_{\text {eff }}\right)$.
The correct statements are

Which of the following relation correctly described all the lines in the hydrogen spectrum?

The number of nodal planes ‘d’ orbital has

In hydrogen atom, which energy level order is not correct:

From the discharge tube experiment, it is concluded that:

A particle A moving with a certain velocity has the de-Broglie wavelength of 1 A°. For particle B with mass 25% of A and velocity 75% of A, calculate the de-Broglie wavelength

Hydrogen like atom with atomic no ' $\mathrm{Z}$ ' is in a higher excited state of quantum no. ' $n$ '. This excited state can make a transition to the first excited state by successively emitting two photons of energies $20 \mathrm{ev} \& 28.3 \mathrm{ev}$ respectively. Alternatively the atom from the same excited state can make transition to the $2^{\text {nd }}$ excited state by emitting photons of energies $8.0 \mathrm{ev} \& 10.13 \mathrm{ev}$ respectively. Determine ' $\mathrm{Z}$ '

The compound in which cation is isoelectronic with anion is

The electron possesses wave properties was shown experimentally by:

Which of the following statements are correct?

(i) The second period $(n=2)$ starts with lithium and third electron enters the $2 s$ orbital. The next element, beryllium has four electrons and has the electronic configuration $1 s^2 2 s^2$. From the next element boron, the $2 p$ orbitals are filled with electrons when the $\mathrm{L}$ shell is completed at neon $\left(2 s^2 2 p^6\right)$. Thus there are 8 elements in the second period.

(ii) Successive filling of $3 s$ and $3 p$ orbitals gives rise to the third period of 8 elements from sodium to argon.

(iii) The fourth period $(n=4)$ starts at potassium and the added electron fill up the first $4 s$ and $4 p$ orbitals than $3 d$ orbital is filled.

(iv) Fifth period begins with rubidium with the filling of $5 \mathrm{~s}$ orbital and ends at xenon with the filling up of the $5 p$ orbital.

Statement I: Electrons are negatively charged.

Statement II: The application of electric and magnetic field deflected the rays in the discharge tube towards the positive plate.

Kinetic energy of an electron in hydrogen atom increases after transition from an orbit $n_1$ to another orbit $n_2$. Then

The Heisenberg^' s uncertainty principle can be applied to:

How many moles of $\mathrm{He}$ are produced when one mole of ${ }_{92} \mathrm{U}^{238}$ disintegrates into ${ }_{82} \mathrm{~Pb}^{206}$?

Positive charge in an atom is:

The nodes present in 3p-orbitals are

Which of the following conclusions could not be derived from Rutherford’s $\alpha$ - particle scattering experiment

Visible spectrum of hydrogen shows that it exists in two different forms which are based on direction of spin of the:

Assertion : ${ }_{11}^{22} {Na}$ emits a position giving ${ }_{12}^{22} {Mg}$.

Reason : In $\beta^{+}$emission neutron is transformed into proton.

The number of s-electrons present in an ion with 55
protons in its unipositive state is

The emission spectrum of hydrogen is found to satisfy the expression for the energy change, ∆E (in joules), such that $\Delta E = 2.18 \times {10^{ - 18}}\left[ {\frac{1}{{n_1^2}} - \frac{1}{{n_2^2}}} \right]$ J, where, ${n_1} = 1,2,3,\; \ldots$ and ${n_2} = 2,3,4, \ldots$ The spectral lines correspond to Paschen series are