The binding energy of the electron in a hydrogen atom is $13.6\, eV$, the energy required to remove the electron from the first excited state of $Li^{++}$ is ......... $eV$
$122.4$
$30.6$
$13.6$
$3.4$
The wavelength of the first line of Balmer series of hydrogen atom is $\lambda \,\mathop A\limits^o $. The wavelength of this line of a double ionised lithium atom $(Z = 3)$is
To accommodate the view that matter is made up to $5$ elements only, a scientist proposed the following hypothesis; that atoms can have a maximum principal quantum number $n _{\operatorname{man}}$ and no higher. Then, which of the following statements must be true ?
Answer the following questions, which help you understand the difference between Thomson's model and Rutherford's model better.
$(a)$ Is the average angle of deflection of $\alpha$ -particles by a thin gold foil predicted by Thomson's model much less, about the same, or much greater than that predicted by Rutherford's model?
$(b)$ Is the probability of backward scattering (i.e., scattering of $\alpha$ -particles at angles greater than $90^{\circ}$ ) predicted by Thomson's model much less, about the same, or much greater than that predicted by Rutherford's model?
$(c)$ Keeping other factors fixed, it is found experimentally that for small thickness $t,$ the number of $\alpha$ -particles scattered at moderate angles is proportional to $t$. What clue does this linear dependence on $t$ provide?
$(d)$ In which model is it completely wrong to ignore multiple scattering for the calculation of average angle of scattering of $\alpha$ -particles by a thin foil?
What radioactive source did the Geiger and Marsden use in the scattering experiment?
Apply Bohr’s atomic model to a lithium atom. Assuming that its two $K$-shell electrons are too close to nucleus such that nucleus and $K$-shell electron act as a nucleus of effective positive charge equivalent to electron. The ionization energy of its outermost electron is......$eV$