1. Write the symbols of the three isotopes of carbon.
2. Which isotope is used to find the age of prehistoric objects ?
3. Name one important component of “printers ink”.
4. Define the term allotropy.
5. Name the three common allotropes of carbon.
Answers
Answer
1. Isotopes of an element share the same number of protons but have different numbers of neutrons. Let's use carbon as an example. There are three isotopes of carbon found in nature – carbon-12, carbon-13, and carbon-14. All three have six protons, but their neutron numbers - 6, 7, and 8, respectively - all differ.
2. Carbon-14, or radiocarbon, is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons. Its presence in organic materials is the basis of the radiocarbon dating method pioneered by Willard Libby and colleagues to date archaeological, geological and hydrogeological samples.
3. The base ingredient of printer ink is usually oil; either linseed oil, soybean oil, or a petroleum distillate. Carbon black and varnish are combined to make basic black ink. Colored ink are made with dyes/compounds like peacock blue, yellow lake, diarylide orange, and phthalocyanine green.
4. the ability that certain substances have to exist in more than one physical form
5. Diamond, graphite and fullerenes (substances that include nanotubes and 'buckyballs' , such as buckminsterfullerene) are three allotropes of pure carbon.