THE MODERN PERIODIC TABLE

Modern Periodic Table

Mendeleev                     1834 - 1907 1869 – Dmitri Mendeleev published the first periodic table

Mendeleev Born in Siberia, the last of 14-17 children Father blind, mother ran glass factory When he finished high school, his father died and the factory burnt down

Mendeleev His mother took him to St. Petersburg to study science Denied admission to the university, he studied at a school for teachers

Mendeleev In time, he became a professor of chemistry at the U. of St. Petersburg While writing a chemistry textbook, he developed the periodic table

Mendeleev Where a gap existed in his table, he predicted a new element would be found and deduced its properties He was right. Three elements were found during his lifetime Ga, Sc, Ge

Mendeleev The discovered elements provided the strongest support for his periodic table It is a cornerstone in chemistry and in our understanding of how the universe is put together

Mendeleev Mendeleev’s table arranged the elements in order of increasing atomic mass

Modern Periodic Table Square of the periodic table contains an                                                                                                                       Square of the periodic table contains an element’s atomic #, chemical symbol, atomic mass

Modern Periodic Table The elements in each group have the same number of valence electrons

METALS Most elements are metals 88 elements in total

Physical Properties of Metals Luster (shininess) Good conductors of heat and electricity High density (heavy for their size) High melting point Some metals (Fe, Co and Ni) are magnetic

Physical Properties of Metals Ductile (most metals can be drawn out into thin wires) Malleable (most metals can be hammered into thin sheets)

Chemical Properties of Metals Metals show a wide range of chemical properties Reactivity – ease and speed with which an element combines or reacts Group 1 and 17 VERY reactive

Chemical Properties of Metals Some metals are very reactive, some do not react easily Alloy – mixture of metals Examples: bronze, brass, stainless steel

Chemical Properties of Metals Easily lose electrons (Group 1 and 2) Corrode easily. Corrosion is a gradual wearing away Examples of corrosion: silver tarnishing and iron rusting

Families of Metals

Group 1 – Alkali Metals

Group 1 – Alkali Metals One valence electron Most reactive of all metals Soft Low densities Low melting point

Group 1 – Alkali Metals Na, K Na compounds in found in sea water Na and K both essential for life

Group 1 – Alkali Metals

Group 2 – Alkaline Earth Metals Two valence electrons Group 2 Very reactive

Group 2 – Alkaline Earth Metals Magnesium and calcium are common alkaline earth metals Calcium compounds make up much of your bones and teeth

Group 2 – Alkaline Earth Metals

Transition Metals

Transition Metals Elements in Groups 3 – 12 Bridge between very reactive metals on left side and less reactive metals on the right side

Rare Earth Metals Two rows on the bottom of the table Lanthanides and Actinides Lanthanides are soft, shiny metals with high conductivity Actinides are all radioactive.

NONMETALS Nonmetals are found to the right of the stair step line - 17 elements in total Make up most of the human body (oxygen, carbon, nitrogen and hydrogen)

Physical Properties of Nonmetals The physical properties of nonmetals are opposite to those of metals

Physical Properties of Nonmetals No luster (dull appearance) Poor conductor of heat and electricity Brittle (breaks easily) Not ductile Many are gases at room temperature

Physical Properties of Nonmetals Not malleable Low density Low melting point Elements in this group have one valence electron How does this affect their reactivity? It makes them VERY REACTIVE.

Chemical Properties on Nonmetals Have many electrons in their highest energy level (shell) Form negative ions Gain electrons Noble gases do not react with other elements (OUTER SHELL IS FULL)

Chemical Properties of Nonmetals Diatomic molecule – when nonmetals form molecules of two identical atoms H H

METALLOIDS Elements that border the zigzag line Have properties of both metals and nonmetals 7 in total Silicon, Boron, Antimony, Arsenic, Tellurium

Physical Properties of Metalloids Solids Can be shiny or dull Conduct heat and electricity better than nonmetals, but not as well as metals

Chemical Properties of Metalloids Tend to gain and lose electrons React with metals to form salts Some act like metals, some act like nonmetals

Carbon Group Carbon is the only nonmetal in Group 14 Two common forms – graphite and diamond Each element has four valence electrons                                                                                 

Group 15 – Nitrogen Group N and P are nonmetals N makes up 80% of air N is essential to life

Group 17 -- Halogens Halogens combine with metals to form salts Have 7 valence electrons MOST REACTIVE of NON-metals

Group 18 – The Noble Gases Colorless gases Do not bond or combine with other elements Outer electron shell is full

Group 18 – The Noble Gases He is the second lightest gas

Hydrogen H does not fit in with any group (yet can be in either GROUP 1 or GROUP 17) Reacts easily with other elements

QUIZ YOURSELF! What are the rows across the periodic table called? Answer: PERIODS                                                                              

QUIZ YOURSELF! What is the term for the vertical columns in the Periodic Table? Answer: Groups or Families                                                                              

QUIZ YOURSELF! How are the elements arranged in the periodic table? In order of increasing atomic number                                                                                                                      

QUIZ YOURSELF! ALKALI METALS -- GROUP 1 What is the most reactive group of metals? ALKALI METALS -- GROUP 1