The Periodic Table

Why is the Periodic Table important to me? Useful tool for chemists Helps us predict the physical and chemical properties of an element based on its location (row and column)

Before the table was developed… Element organization was a mess. Imagine going to a grocery store with no organization!! Difficult to find information. Chemistry didn’t make sense. Dalton 1800’s Gmelin 1843

Chancourtois (1862) and Newland (1863) Organized by increasing atomic masses, and observed a repeating pattern to the properties of the elements, but this pattern fell apart after Calcium.

Dmitri Mendeleev: Father of the Table Russian Chemist Mendeleev observed the relationship between the elements increasing atomic mass and repetitive pattern of physical and chemical properties. Published the first version of the periodic table in 1869

Mendeleev’s Table Gaps existed in his table (marked with a “?”) He was able to predict the properties of these missing elements long before they were discovered.

Mendeleev’s Predictions “Ekasilicon” Germanium Notice how Mendeleev’s predictions (orange column) were very accurate when compared to Germanium’s actual characteristics (green column) Date Predicted 1871 Date Discovered 1886 Atomic Mass 72 72.6 Density 5.5 g/cm3 5.47 g/cm3 Bonding Power 4 Color Dark Gray Grayish White

Put elements in rows by increasing atomic mass. How his table worked: Put elements in rows by increasing atomic mass. Put elements in columns by the way they reacted. Some Problems: He left blank spaces for what he said were undiscovered elements. He broke the pattern of increasing atomic weight to keep similar reacting elements together. http://www.youtube.com/watch?v=fPnwBITSmgU http://www.youtube.com/watch?v=cvRcUeWjBu0

Periodic Law Mendeleev stated that the physical and chemical properties of elements repeated according to a pattern. Similar elements were placed in the same column.

Henry Moseley (1887-1915) Made improvements to Mendeleev’s Periodic Table Moseley discovered that the periodic nature of the elements wasn’t due to atomic mass, but by atomic number. He arranged the table by atomic number instead. Realized that there were undiscovered elements

The Current Periodic Table The horizontal rows are called periods and are labeled from 1 to 7. Each period has a new electron energy level

Periods go across

The vertical columns are called groups are labeled from 1 to 18. Each group has the same number of electrons in the outermost energy level. (valence electrons) http://www.youtube.com/watch?v=7mLPC74GHMo

Summary of the Table’s arrangement Elements are arranged by increasing atomic number Elements in the same period have the same number of electron energy levels Elements in the same group the same number of valence electrons Valence electrons are the electrons found in the outermost energy level.

Valence electrons-How many electrons are in the outermost shell? Si Ge

Element Superhero Project

Learn about your element It’s history It’s physical and chemical properties It’s periodic table location and family Create a superhero for your element displaying its characteristics such as strengths and weaknesses, its hideouts, and super powers.

Families on the Periodic Table Columns are also grouped into families. Families may be one column, or several columns put together. Families have names rather than numbers. (Just like your family has a common last name.)

Families of the Periodic Table

Families of Elements 1 Alkali Metals 2 Alkaline Earth Metals 3-12 Transition Metals 13 The Boron Family 14 The Carbon Group 15 The Nitrogen Group 16 The Oxygen Group 17 The Halogens 18 The Noble Gases Lanthanide Series Actinide Series

Transition Elements Groups 3-12 Transition Elements All transition elements are metals. Group 11 (The Coinage Metals) The Lanthanides The Actinides

Hydrogen Hydrogen belongs to a family of its own. Hydrogen is a diatomic, reactive gas. Hydrogen was involved in the explosion of the Hindenberg. Hydrogen is promising as an alternative fuel source for automobiles

Alkali Metals 1st column on the periodic table (Group 1) not including hydrogen. Very reactive metals, always combined with something else in nature (like in salt). Soft enough to cut with a butter knife

Alkali Metals http://www.open.edu/openlearn/science-maths-technology/science/chemistry/alkali-metals

Alkaline Earth Metals Second column on the periodic table. (Group 2) Reactive metals that are always combined with nonmetals in nature. Several of these elements are important mineral nutrients (such as Mg and Ca)

Transition Metals Elements in groups 3-12 Less reactive harder metals Includes metals used in jewelry and construction. Metals used “as metal.”

Boron Family Elements in group 13 Aluminum metal was once rare and expensive, not a “disposable metal.”

Carbon Family Elements in group 14 Contains elements important to life and computers. Carbon is the basis for an entire branch of chemistry. Silicon and Germanium are important semiconductors.

Nitrogen Family Elements in group 15 Nitrogen makes up over ¾ of the atmosphere. Nitrogen and phosphorus are both important in living things. Most of the world’s nitrogen is not available to living things. The red stuff on the tip of matches is phosphorus.

Oxygen Family or Chalcogens Elements in group 16 Oxygen is necessary for respiration. Many things that stink, contain sulfur (rotten eggs, garlic, skunks,etc.)

Halogens Means salt former Elements in group 17 Very reactive, volatile, diatomic, nonmetals Always found combined with other elements in nature . Used as disinfectants and to strengthen teeth.

The Noble Gases

The Noble Gases Elements in group 18 VERY unreactive, monatomic gases Used in lighted “neon” signs Used in blimps to fix the Hindenberg problem. Have a full valence shell.

http://www.open.edu/openlearn/science-maths-technology/science/chemistry/noble-gases

http://www.youtube.com/watch?v=Uy0m7jnyv6U Meet the Elements http://www.youtube.com/watch?v=-wu0LixSBpk

http://laughingsquid.com/the-periodic-table-of-elemental-discoveries-by-country/

Families on the Periodic Table Elements on the periodic table can be grouped into families bases on their chemical properties. Each family has a specific name to differentiate it from the other families in the periodic table. Elements in each family react differently with other elements.

Periods Each row is called a “period” The elements in each period have the same number of shells 1st Period = 1 Shell 2nd Period = 2 Shells 3rd Period = 3 Shells 4th Period = 4 Shells www.chem4kids.com

Groups Group 8 = 8 electrons Group 1 = 1 electron Except for He, it has 2 electrons Group 2 = 2 electrons Each column is called a “group” 3, 4, 5, 6, 7 Each element in a group has the same number of electrons in their outer orbital, also known as “shells”. The electrons in the outer shell are called “valence electrons” www.chem4kids.com

Periodic table song http://www.youtube.com/watch?v=zUDDiWtFtEM&feature=youtube_gdata_player "Hunting the Elements" NOVA special https://www.youtube.com/watch?v=wsoZFTC02PY (2012) NOVA show Hunting The Elements   http://www.pbs.org/wgbh/nova/physics/hunting-elements.html lecture series with Peter Wothers is really, really good: The Modern Alchemist: Air : Ri Channel  It covers something we all experience with every breat