How many neutrons can an atom hold?

Now, I think that I've mentioned that there is a theory that the interaction between the protons and the neutrons keeps the nuclei of atoms stable. Which is why most atoms occuring in nature do not deviate from the 1:1 ratio too much without being radioactive. The research in this area is still ongoing with lots of interesting news which really can be so ground breaking that it can change what we know/understand sometimes. Case in point:

A group of scientist, from Michigan State University, who were working on heavy aluminium and magnesium, found that the protons and neutrons do not have to be evenly numbered. With neutrons twice the number of protons, some heavy aluminium and magnesium were found with stability long enough for detection. (of course they decay shortly afterwards)

"They fired a beam of high-energy calcium ions into a sheet of tungsten, producing new elements. Among them, neutron-rich versions of aluminium and magnesium could be spotted in the few milliseconds before they decayed.

The researchers found an isotope of magnesium with 28 neutrons (magnesium-40) — more than twice its normal complement. That's bigger than the previous heaviest magnesium isotope found, which had 26 neutrons."

Read more about it in an article with the same title @ Nature (Published online 24 October 2007 | Nature | doi:10.1038/news.2007.189). Log-in using the NLB Digital library.

Heavy Water

Ever heard of the term "heavy water"? It's the common name of what is also known as deuterated water, D₂O. It is formed by the 2 isotopes of hydrogen deuterium. As deuterium is twice the mass of protium (the most common form of hydrogen), this water is "heavy". In fact, it is so "heavy" that its ice sinks in water.

Like typical Singaporeans, your next question most likely is "can drink or not?".
And the answer is yes, but not in a large quantity. Because it behaves chemically like water, it is not toxic. However, since deuterated water does have some physical properties that is different from our usual water, if we consume just pure deuterated water over a period of time, biological processes will be affected.

Read more about it here.

Do atoms ever break down?

Actually they do, but definitely not through our usual chemical reactions. The process is actually quite familiar to many of us. It's called nuclear reaction (because it causes change at the heart of the atoms, the nucleus).Given the same "logic" we can "make" new atoms as well.

There are 2 primary nuclear reactions, nuclear fission (splitting of the nucleus) and nuclear fusion (fusing particles to form a new nucleus). These reactions usually result in a large amount of energy being given off (hence nuclear bomb) mostly in the form of radiation.

Someone asked me about alpha, beta and gamma rays today (all 3 being forms of radiation). I apologise for being vague about beta radiation, cos beta decay is a little complicated. For that I did a websearch and found a pretty good site, for those who are interested in higher level stuff, please go here. For the unintiated it may be a little tough to understand, but it's interesting read outside the syllabus.

Sometimes scientists get hungry too...

Long before the quantum model of the atom as we know today is established, scientists thought that the atom resembles a plum pudding in structure. In case the word "plum pudding" doesn't sound like something you know, think of it as a fruit/raisin cake-like dessert which is traditionally served at christmas. Just so you know, there is no "plum" nor "pudding" (as we know it) in this dish. For those of us who still have no clue, take a look at this.

J.J. Thompson, a nobel laureate, was the first to discover electrons. He thought that these negative electric charges are planted randomly into a positively charged sphere much like the raisins in a plum pudding. Perhaps it he was in a festive mood, or just simply hungry. However this discovery of the electrons was revolutionary and he later earned his nobel prize for his work. Read more about it here.