(a) State three conclusions that can be drawn from Rutherford’s experiment on the scattering of alpha particles by a thin metal foil in relation to the structure of the atom
The diagram above illustrates th3 energy levels of an electron in an atom. If an excited electron moves from n\(_2\) to n\(_\theta\), calculate the:
(i) frequency;
(ii) wavelength of the emitted radiation. [ h = 6.6 x 10\(^{-34}\) Js; le V = .6 x 10\(^{-19}\) J; C = 3.0 x 10\(^8\) ms\(^{-1}\)]
(c) The following nuclear equations represent two types of radioactivity.
\(^{226}_{88}R_a \to ^{222}_{86}R_n + ^a_2a\) (Equation A)
\(^{14}_7N + ^4_2a \to ^{17}_8O + ^1_1p\) (Equation B)
Identify each type and explain briefly the difference between them
Explanation
(a) Conclusion from Rutherford's experiment;
- The nucleus is massive
- Most of the atom is empty space
- The nucleus is positively charged
- Electrons revolve round the nucleus
- It explains the periodicity of elements in the periodic table
b )(i) E\(_2\) = E\(_2\) - E\(_o\)
= - 2.0 - (-12.0)
= 10.0 e V
= 10 x 1.6 x 1O\(^{-19}\)J
= 1.6 x 10\(^{-18}\)J
E = hf
Or
f = E/h
= 1.6 x 10\(^{18}\)
= 6.6 x10\(^{-34}\)
= 2.424 x 10\(^{15}\) Hz
(ii) c = fλ
λ= c/f
= 3 x 10\(^8\)
2.424 x 10\(^{15}\) Hz
(c) A: Natural radioactivity
B: Artificial radioactivity
Any correct difference
