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Daily Science Pg. 44. Write the short hand configurations for the following elements: Molybdenum, Selenium, Strontium, Ruthenium, and Antimony Write the number of valence electrons the previous elements have Based on its group, how many valence electrons will Bromine have? Prove this.
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Daily SciencePg. 44 • Write the short hand configurations for the following elements: • Molybdenum, Selenium, Strontium, Ruthenium, and Antimony • Write the number of valence electrons the previous elements have • Based on its group, how many valence electrons will Bromine have? Prove this. • Draw the electron dot diagram for Oxygen and Silicon
The Periodic Table Pg.43
History • http://www.youtube.com/watch?v=0RRVV4Diomg
Discovery • Only knew 23 elements in 1790 • Discovery of electricity brought change • Dmitri Mendeleev demonstrated a connection between atomic mass and elemental properties (1869) • Saw a repeating pattern • Left blank spaces where undiscovered elements should go (Sc, Ge, and Ga) • Henry Moseley rearranged the table according to atomic number • A clear repetition of repeating physical and chemical patterns emerged. Called periodic law
The Modern Periodic Table • The columns on the periodic table are called groups (or families) • Elements in the same group have similar chemical and physical properties • The rows are called periods • Main group elements (representative elements): Groups 1-2, 13-18 • Transition elements: Groups 3-12 • Sometimes see a number/letter system • Can find elements based on group and period
Major groups • There are 3 major groups on the periodic table: • Metals • Nonmetals • Metalloids (or semiconductors)
Metal • The metals are on the left side of the periodic table • Malleable and ductile • Shiny • Good conductors of heat and electricity • They further broken into 4 categories • Alkali metals • Alkaline Earth metals • Transition elements • Inner transition elements
Nonmetals • Are on the right side of the stair-step (except H) • Can be gases • Brittle and dull • Poor conductors of heat and electricity • Br only nonmetal that is a liquid at room temp • Can be broken into smaller categories • Halogens • Noble gases • Carbon group
Metalloids • Border the stair step line • Have properties of both metals and nonmetals • Si and Ge most important as they are used in computer chips