BIOL 1110 Lecture Notes - Lecture 11: Sodium Chloride, Blood Plasma, Phloem
Document Summary
What are elements composed of: atoms the building blocks of elements, protons positively charged particles (p+) found in nucleus. If number of protons = number of neutrons neutral. However, if an atom loses/gains an electron, its referred to as an ion. Mainly nonmetals: neutrons no charge (n0) located in nucleus, electrons negatively charged particles (e-) orbitals around nucleus e- orbit within orbitals and occupy the lowest energy orbital available to them. Important from biological standpoint: atomic mass number. Not the same as atomic number: total of p+ and n0, all atoms of a particular element have the same number of p+ Isotope different n0 number forms of the same element. Use ratios of isotopes to date fossil/archaeological items carbon dating. Use isotopes to start to put together phylogenies. Classified as radioactive an isotope that"s emitting energy as rays or particles until stable. There"s a number of uses for radioactive isotopes:
