PHYSICS 20E Lecture Notes - Lecture 6: James Ussher, Equinox, Edmond Halley
Document Summary
Lecture 6: the nature of matter and antiquity of earth. Atoms are composed of a heavy nucleus of protons and neutrons orbited by electrons. Nucleus of heavy subatomic particles: protons and neutrons. Only 1 part in 1015 of the space is occupied. The rest if threaded by electromagnetic fields. The chemical elements are distinguished by the number of protons in the nucleus. Number of e = number of p. Each shell can hold x number of electrons. Going down periodic table - adding outer shells for more electrons. Outer shell electrons dictate what chemical compounds are possible. John dalton found c & h combined like this: 1 part c and 4 parts h and get methane. Mendeleev noticed that si and c had similar bonding properties. 1 part si and 4 parts h. That"s why si and c behave in similar ways. Could be a si based life form. An element can have different number of neutrons.
