NATS 1610 Lecture Notes - Lecture 13: Electron Shell, Valence Electron, Relative Atomic Mass

• School: York University
• Department: Natural Science
• Course: NATS 1610
• Professor: Barbara Czaban

Document Summary

Because of atomic structure (i. e. their atomic anatomy) Everything in our world is made of elements. Human body is composed of four elements: carbon 18, nitrogen 3, oxygen 65, hydrogen 10% Each elements have its own symbols: h hydrogen, na sodium. Atom are the smallest unit that have properties of a given element. Atoms consists of 2 areas and 3 kinds of subatomic particles: central nucleus contains positively charged protons and neutral neutrons, electron cloud (electron shell) contains negatively charged electrons and more rapidly around the nucleus. All atoms of an element have the same atomic number. Written as a subscript to lower left of atomic symbol. Weight of protons + neutrons: protons and neutrons each = 1 atomic mass (amu, electron are light and have almost no mass. Written as a superscript to upper left of atomic symbol. Have the same number of protons and electrons. Electron orbit around the atom nucleus inside various shells around nucleus.