Francium is a natural chemical element but the total quantity of francium in the earth crust is only approx. 30 g. Francium has ca. 40 isotopes and isomers but only two are natural: 221Fr (in the neptunium decay chain series) and 223Fr (in the actinium decay chain series). Artificially preparation of francium isotopes is also extremely difficult and expensive; and the chemistry and physics of isotopes was developed essentially after 1940. Supplementary, the most stable isotope of francium has a half life of only 21,8 minutes and is strongly radioactive; the half lives of the artificially prepared isotopes are more smaller.
This is sufficient reason to explain why francium was later discovered and why even today is only slightly studied.
Francium is a natural chemical element but the total quantity of francium in the earth crust is only approx. 30 g. Francium has ca. 40 isotopes and isomers but only two are natural: 221Fr (in the neptunium decay chain series) and 223Fr (in the actinium decay chain series). Artificially preparation of francium isotopes is also extremely difficult and expensive; and the chemistry and physics of isotopes was developed essentially after 1940. Supplementary, the most stable isotope of francium has a half life of only 21,8 minutes and is strongly radioactive; the half lives of the artificially prepared isotopes are more smaller.
This is sufficient reason to explain why francium was later discovered and why even today is only slightly studied.
Francium is a natural chemical element but the total quantity of francium in the earth crust is only approx. 30 g. Francium has ca. 40 isotopes and isomers but only two are natural: 221Fr (in the neptunium decay chain series) and 223Fr (in the actinium decay chain series). Artificially preparation of francium isotopes is also extremely difficult and expensive; and the chemistry and physics of isotopes was developed essentially after 1940. Supplementary, the most stable isotope of francium has a half life of only 21,8 minutes and is strongly radioactive; the half lives of the artificially prepared isotopes are more smaller.
This is sufficient reason to explain why francium was later discovered and why even today is only slightly studied.
no he had been lookng for tuts tomb for over 5 years
Maybe. Scientist found a calendar from the Mayans, and it is over hundreds of years old. The Mayans had a calendar and predictions about the world. Scientist discovered that the Mayans predicted that the world would end on 2012. Hundreds of years ago, the Mayans predicted that astronauts would land on the moon, and as many years passed by, we have astronauts that landed on the moon! So if their prediction was right, does this mean that their prediction of the world ending on 2012 is going to be true also?....
He didn't "discover hieroglyphs", since they were all over Egypt on monuments and tombs and people had known about them for thousands of years before he was born. He helped to translate hieroglyphs, which is not the same thing.
yes it has changed over many years
his education was that he discover the modern physics. with out that we would be over weight people that's why its very important that he dicoverd that (:
It is highly unstable. The MOST stable isotope of this stuff has a half life of 22 minutes.
Please see this article for more details.
The ozone hole was discovered by Dr. Farman. He discovered it over Antarctica.
At a temperature over 677 0C francium may be a gas.
Francium is a natural chemical element but the total quantity of francium in the earth crust is only approx. 30 g. Francium has ca. 40 isotopes and isomers but only two are natural: 221Fr (in the neptunium decay chain series) and 223Fr (in the actinium decay chain series). Artificially preparation of francium isotopes is also extremely difficult and expensive; and the chemistry and physics of isotopes was developed essentially after 1940. Supplementary, the most stable isotope of francium has a half life of only 21,8 minutes and is strongly radioactive; the half lives of the artificially prepared isotopes are more smaller. This is sufficient reason to explain why francium was later discovered and why even today is only slightly studied.
The early humans discovered and started to use fire some 500,000 years ago. It took hundreds of thousand years to discover how to make fire.
cells
Archimedes
just over 1200 years :)
Tin is one of the earliest known metals and is over 5550 years old.
The evidence that scientist have that erosion works slowly over a long period of time is that Arizona is the result of close to three million years of erosion.
i believe it would be 250 degrees over the next 100 years.