Periodic Table Def.-A periodic table is a chart of elements arranged into rows and columns according to their physical and chemical properties. Pg 391 --Periodic means– the table has repeating cycles or patterns (392) Row also called a period. Atomic number increases by one moving from left to right across search period. Columns also called groups or families. Groups have similar chemical and physical properties.

Mendeleev created first useful table of elements in 1869 Mendeleev’s periodic table was organized by increasing atomic mass. At the time the table was constructed there were only approximately 60 known elements. Mendeleev studied chemical reactivity. Mendeleev studied physical properties such as: Density Color Melting point Atomic Mass Mendeleev’s predictions Mendeleev had several large gaps in atomic mass, in his periodic table. He predicted that three new elements would be discovered and he also predicted their properties. Both came true. (Gallium, Scandium and Germanium)

Henery Mosley is a physicist that arranged the modern periodic table in 1900 Mosley’s table is arranged in order of increasing atomic number. Groups (columns)or families on the table are numbered 1-18. Families react in similar ways. Patterns to physical PROPERTIES DEVELOP. PERIODS- ROWS ON THE PERIODIC TABLE. ATOMIC NUMBER INCREASES BY ONE FROM LEFT TO RIGHT. Metals are located on left side of the table. ¾ of all elements are metals Non metals are on the right side. (exception is hydrogen) Metalloids are located between metals and nonmetals. (zig-zaG LINE)

Element Key

Horizontal row Called a__________

Vertical Column Called a ______ or _____

Blank periodic table Group names? 3

Section 2 Metals All elements in groups 1-12 are metals except hydrogen. Some elements in groups 13-15 are metals. Metal properties of elements increase as you move from right to left and top to bottom on the periodic table Metal physical properties Shiny (luster) Malleable and ductile (most metals are not brittle.) Good conductors of heat and electricity In general density, strength, boiling pointy, melting point are greater than other elements. Metals in the same group/family have similar chemical properties. (Pg 405)

Alkali Metals Group 1 Most reactive metals. (therefore do not occur naturally in elemental form) Reactivity increases from top to bottom. (francium is the most reactive metal) Located on the far left of the periodic table Physical properties Soft –can be cut with a butter knife Low density Shiny silver appearance Malleable and ductile Good conductor of heat and electricity

Alkaline Earth Metals group 2 React quickly with other elements (not as quickly as group 1) do not occur naturally in elemental form. Reactivity increases from top to bottom. Located on the left side of the periodic table Physical properties –(all properties are less than group 1) Soft but not as soft as group 1 Low density but not as low as group 1 Shiny silver appearance Malleable and ductile Good conductor of heat and electricity

Transition elements Groups 3-12 including Lanthanide and actinide Large group of elements located in the main part of the periodic table All transition elements are metals Transition elements have higher melting points, greater strength, and higher density than that of groups1 and 2. Most all metals are solid at room temperature. Exception is mercury which is only metal that is liquid at room temperature. Often used by artist because they are very colorful

Non metals Properties of nonmetals: many are gases at room temperature solid non metals are dull Poor conductors of heat and electricity (good insulators)

Elements of life 96% of body mass comes from just 4 elements—oxygen, carbon, hydrogen, and nitrogen. All Nonmetals Most all living things contain the element carbon.

Halogens Group 17 Halogen refers to elements that can react with metals to form a salt. Halogens only occur naturally as compounds because they react so readily. They can even form compounds with other nonmetals. In general: as you move down on the periodic table the halogens become less reactive.

Noble gases group 18 Noble Gases are located on the far right of the table and do not normally react with other elements to form compounds.

Hydrogen Family Hydrogen is most common element in the universe. More than 90% of all the atoms in the universe are hydrogen. Under normal atmospheric conditions it behaves as a nonmetal.

Metalloids Metalloids located along the zig-zag line between the metals and nonmetals on the periodic table. Metalloids share chemical and physical properties of both metals and nonmetals The most abundant metalloid in the universe is silicon. Semiconductors conduct electricity at only high temperatures and act as insulators at low temperatures. Metalloids often act as semiconductors.