What is the atomic number of gold ? 

In Rutherford scattering experiment, what will be the correct angle for $\alpha $ scattering for an impact parameter $b = 0$.....$^o$

Suppose you are given a chance to repeat the alpha-particle scattering experiment using a thin sheet of solid hydrogen in place of the gold foil. (Hydrogen is a solid at temperatures below $14\; K$.) What results do you expect?

Given below are two statements:

Statement $I$: Atoms are electrically neutral as they contain equal number of positive and negative charges.

Statement $II$: Atoms of each element are stable and emit their characteristic spectrum.

In the light of the above statements, choose the most appropriate answer from the options given below.

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......$eV$

In the Rutherford experiment, $\alpha -$ particles are scattered from a nucleus as shown. Out of the four paths, which path is not possible?