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Development of the Periodic Table

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Presentation on theme: "Development of the Periodic Table"— Presentation transcript:

1 Development of the Periodic Table

2 Noticed that trends repeat every 8th element
John Newlands First periodic table Noticed that trends repeat every 8th element Developed the 14 known elements of the time by masses Developed the Law of Octaves (repeat every 8) Ex: Valence Electrons He did this in 1864 Only 14 elements were known at the time

3 Meyer and Mendeleev Lothar Meyer (German) and Dmitri Mendeleev (Russian) Created the modern periodic table around the same time but they did not work together Mendeleev is given more credit because he published his work first Mendeleev left blank spaces Undiscovered elements Predicted the properties of these elements They did this in 1869 Mendeleev’s predictions were almost perfect as far as atomic properties, appearance, and reactions Ex: Germanium, Scandium, Gallium

4 Henry Moseley Rearranged the periodic table No longer by masses
Now by atomic numbers Periodic Law Periodic repetition of chemical and physical properties of the elements when they are arranged by increasing atomic number In 1913 noticed that atomic masses were not the most accurate way to set up the periodic table. Some elements were not in the proper place So he rearranged the table by atomic number, which completed all of the periodic patterns

5 Metals, Non-Metals, and metalloids
Most are malleable and ductile Generally shiny Most are solid at room temperature Good conductors of heat and electricity Non-metals Typically gases or brittle/dull looking solids Poor conductors of heat and electricity Most abundant element in the human body is a nonmetal Metalloids Properties of both metals and nonmetals Metals: Malleable=sheets Ductile=wire Shiny when clean and smooth Nonmetal: most abundant in human body is oxygen

6 Elements of the same row, fill in their electrons on the same shell
Rows (left to right) Also known as PERIODS Elements of the same row, fill in their electrons on the same shell Have similar properties: Atomic radius size Ionization energy electronegativity Shell=energy level

7 Columns (top to bottom)
Known as FAMILIES/GROUPS Have very similar properties Same number of valence electrons Similarities are more significant than those of periods Reactiveness Bonding Physical properties (malleable/ductile/luster) *Similarities in Families Similarities are more significant than periods except for those of the lanthanide and actinide series All the elements in the halogen family are very reactive with water The more the elements want to create bonds (due to number of valence electrons) the more reactive they tend to be

8 Family/Group 1: Alkali Metals
Very reactive (1 valence electron) Shiny Light weight Soft metals Malleable/bendable Low melting points React violently in water Easily form salts Never found in the pure form in nature Uses: greases, batteries, salts, gasoline, fertilizers, and photography Soft metals- so soft can sometimes be cut with a dull knife Would not use for coins, houses, etc

9 Family/Group 2: Alkaline Earth Metals
Highly reactive metals All have 2 valence electrons High melting points High densities Tarnish in air Never found in the pure form in nature Good conductors Uses: Fireworks, alloys, nuclear reactors, cancer treatment, etc.

10 Transition Metals Middle section of the periodic table
Hard, strong, and shiny High melting points High densities Good conductors Never found in the pure form in nature Uses: Alloys, pipes, jewelry, cars, catalyst The elements are in the D sub-block – these transition in out of charges (transition metals) They have their own chemistry – known as inorganic chemistry

11 Inner Transition Metals
Lower two rows Lanthanide Series Rare Earth metals Soft, silvery metal Reactive Poor conductors Uses: Flint, glass, nuclear reactors, television screens, etc. Actinide Series All radioactive Silvery metals 4 are natural/rest are man made Nuclear power, pigment in glass, smoke detectors, atomic bombs (plutonium), metal detectors (americium) etc Lanthanide series is especially reactive with oxygen

12 BCNO Families Four separate but very similar families
Have 3-6 valence electrons Metals, nonmetals, and metalloids Most are solids at room temp. Selectively reactive Uses: Essential to life, electronics, insulators, poisons, fertilizers, etc.

13 Group/Family 7: Halogens
Highly reactive non-metals All have 7 valence electrons Poisonous All states of matter Never found in the pure form Poor conductors Selectively Reactive Very Rare Uses: Toothpaste, cleaner, photography, insecticides, Reactivity decreases as it moves down the column (Fluorine is the most reactive) As atomic number increases rarity also increases, and become less useful.

14 Family/Group 8: Noble Gases
Nonreactive non-metals 8 valence electrons Gaseous state Colorless Tasteless Odorless Uses: Balloons, lights, cancer treatment, headlights (xenon), light bulbs (argon), etc.

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