1. Pre-AP Chemistry

2.  Dmitri Mendeleev lived and worked in Russia  He developed his model of the periodic table in the 1860s, but published it in 1869  Mendeleev arranged the elements by their atomic masses and their properties

3.  Mendeleev left gaps in his periodic table to allow for elements that had not been identified, even predicting their properties

4.  The modern periodic table arranges the elements in rows (periods) by their atomic numbers.  Elements having the same number of valence electrons, and similar properties, are in vertical groups or families.

5.  Characteristics- have one valence e-, form 1+ ions, low density (float ), very reactive, explode when exposed to water, softer than most metals, good conductors of heat and electricity, form salts with halogens  Examples: lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr)

6.  Uses- batteries, lubricants, alloys, gunpowder, salts, paper industry, fertilizer, detergent

7.  Characteristics- very reactive, form 2+ ions, shiny, soft, react vigorously with oxygen  Uses- alloys, Mg is important in chlorophyll, engine parts, Ca needed for teeth and bones, blood clotting, building material, paper, food nutrients  Examples- Be, Mg, Ca, Sr, Ba, Ra

9.  Characteristics- from colored compounds, good conductors of heat and electricity, malleable and ductile, high melting and boiling points (except Hg), can have several oxidation states  Uses- catalysts, corrosion resistant alloys, steel, engines, paint pigments, batteries, building materials, coins  Examples- Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn

11.  Characteristics- solids, semiconductors of heat and electricity, have properties of both metals and nonmetals  Uses- glass, lubricants and adhesives, alloys, transistors, electronics, batteries  Examples- B, Si, Ge, As, Sb, Te, Po

13.  Characteristics- form 2- ions, properties vary (oxygen is a colorless gas, while sulfur is a yellow solid, etc.), “ore-formers”  Uses- oxygen needed for cellular respiration and combustion, sulfur used in gunpowder and rubber, selenium is in solar cells and dandruff shampoo, tellurium is used in paints and lubricants  Examples- O, S, Se, Te, and Po

15.  Characteristics- very reactive, form -1 ions, form salts with metals, all phases of matter represented (gas- F, Cl; liquid-Br; solid- I, At)  Uses- nonstick coatings, glass etching, toothpaste, bleach, disinfectant, pesticides, thyroid hormones, medicines  Examples- F, Cl, Br, I, At

17.  Characteristics- generally nonreactive due to having an octet of valence electrons, odorless gases, conduct electricity and fluoresce, nonflammable  Uses- lighting, lasers, medical imaging and anesthetic (Xe), radiotherapy, balloons  Examples- He, Ne, Ar, Kr, Xe, Rn