During a phenomenon called beta decay the neutron of the isotope uranium 237 emits/releases an electron causing an increase of atomic number. With the reference of a periodic table the "new" element is Neptunium or Np-237.
Answer : The wavelength is 
Solution : Given,
frequency = 29.2 Hz
Formula used :

where,
= frequency
= wavelength
c = speed of light = 
Now put all the given values in this formula, we get the wavelength.

Therefore, the wavelength is 
In terms of a deeper scientific reason, I am not sure, but the basic reason is quite simple. "Mud" tends to look like a mix between a solid, dirt, and a liquid, water or some other liquid. Since it is, in fact, a cross between a solid and a liquid, it has properties of both. It has certain physical and visual properties that only a solid would have, such as texture and opaqueness, but it also has physical properties of a liquid. Since it leans more towards the liquid side than the solid side, we say mud "flows" rather than saying that it "rolls" or "bounces".
Chromium , silver, zinc...
Answer:
The Bayer process is the principal industrial means of refining bauxite to produce alumina (aluminium oxide) and was developed by Carl Josef Bayer. Bauxite, the most important ore of aluminium, contains only 30–60% aluminium oxide (Al2O3), the rest being a mixture of silica, various iron oxides, and titanium dioxide.