CHEM 001A Lecture Notes - Lecture 3: Dmitri Mendeleev, Alkali Metal, Nonmetal
8 Mar 2018
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Radioactive elements: as a star collapses, nuclei begin to disintegrate into protons and neutrons. Individual neutrons may collide and fuse with atomic nuclei in a process called neutron capture. Periodic table (1869), dmitri mendeleev discovered that if arrange elements in order of atomic number, they could be placed in horizontal rows such that elements in vertical columns had similar properties. Compounds (ionic and molecular: compounds substance (fixed composition, definite proportions) usually with two or more elements, models, k k+ + e-; a cation (gives e-,s, br + e- br-; an anion (takes e-,s) Problem: what monatomic ions do the following elements form: nitrogen, neon, aluminum. Molecular compounds: molecular compounds, composed of atoms held together in molecules by covalent bounds, covalent bounds, bond between two atoms created by sharing one or more pairs of electrons, molecular compounds are composed of nonmetals.
