The Periodic TableThe Periodic Table

The Coolest Table in the World

The Periodic The Periodic TableTable

• This is the actual form of the periodic table• The form you usually see is so that less

space is taken up

This portion of the periodic table is usually placed below

The Periodic TableThe Periodic Table

Like this!

A History of the Periodic TableDmitri Mendeleev 1869

• name, atomic mass, and physical and chemical properties of each known element on cards.

• arranged the elements in rows by increasing atomic mass.

• noticed a pattern in the properties of the elements that repeated at regular intervals (periodic).

• arranged the elements in columns such that those in the same column would have similar properties

A History of the Periodic TableDmitri’s Table

• His table had discrepancies. For example, iodine and tellurium. But since they had similar properties, he kept their masses out of order.

• He left gaps in his table and correctly predicted the properties of elements that were yet to be discovered based on the properties of the other elements in the column.

QuickTime™ and aTIFF (LZW) decompressorare needed to see this picture.

QuickTime™ and aTIFF (LZW) decompressor

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Dimitri’s Eerie predictions

• ekasilicon (germanium)– predicted density = 5.5 g/ml– actual density = 5.35 g/mL– predicted mass = 72 amu– actual mass = 72.49 amu– predicted boiling point = 2935 0C– actual boiling point = 2834 0C

SPOOKY

• Worked with Rutherford analyzing line spectra of elements.

• arranged the elements by increasing atomic number to better fit into patterns.

• Mendeleev’s discrepancies disappeared!! Elements were still grouped in columns according to similar properties.

A History of the Periodic TableHenry Moseley (1913)

The Periodic Law• The basis for the periodic table.• States the the physical and chemical properties of

elements are periodic functions of their atomic numbers.

• When elements are arranged in order of increasing atomic number, their physical and chemical properties repeat in a predictable, regular pattern. (repeat in a periodic pattern)

Today’s Periodic Table• Rows/periods - there are 7 rows, corresponding to the number of energy

levels containing electrons in their ground state.

• Columns/groups/families - there are 18 columns. Columns 1A-8A (main group elements) correspond to number of valence electrons present in the element.

• Three major divisions - metals, semi-metals and non metals.1A

2A 3A 5A4A 6A

8A

7A

Properties of Major Divisions

Metals

• lusterous, shiny• typically solids at room

temperature (except Hg, Cs)

• good conductors of heat and electricity

• malleable and ductile• tend to lose electrons easily (form

cations)

Properties of Major Divisions

Nonmetals• do not have a metallic luster• poor conductors of heat and

electricity• may be solid, liquid or gas at

room temperature (majority are gases)

• non malleable, non ductile• tend to gain electrons easily

(form anions)

Properties of Major Divisions

Semi-metals (metalloids)have properties that are

intermediatebetween metals and nonmetals.

The ‘s’, ‘p’, ‘d’ and ‘f’ blocks

The Main Group Elements(the ‘s’ and ‘p’ blocks)

• Main group elements have valence electrons that range from 1 to 8• Same family, same number of valence electrons. That’s why elements in the same

family have similar properties - they have the same number of valence electrons!!!!

These are the Main group elements. They are the most obvious ones to follow the periodic law

Major Groups of the Periodic Table

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Properties of the Major Groups1A alkali metals

• Soft, silvery and shiny

• Highly reactive; combine vigorously with non metals and react with water to form hydrogen gas.

• Are so reactive, are not found as free elements in nature (are always combined with something else!)

• One valence electron

• Uses - example Cs, used for electronic doors

Properties of the Major Groups

2A alkaline earth metals • less reactive than 1A, form bases when react with water (alkaline)

• Still too reactive to be found free in nature

• harder, denser, higher melting points than 1A

• two valence electrons

• Uses - Sr in fireworks (remember the flame color?), Mg used in alloys for lightweight aircraft bodies, Ca important for bones, teeth…

Properties of the Major GroupsD block / transition metals

• Good conductors, harder, more dense with higher melting points than s and p block elements (except Hg)

• Less reactive than s block metals - some are found in their elemental form in nature (Ag, Au, Cu)

• Uses - ‘coinage’ metals due to low reactivity, Ag for photography, W for filaments in light bulbs, Fe mixed with other metals for steel.

Properties of the Major Groups

7A halogens• react with alkali metals to form salts (ionic

compounds)

• Highly reactive and therefore exist as diatomic molecules (F2, Cl2, Br2)

• Distinct colors and odors - all are poisonous.

• At room temperature, fluorine and chlorine are gases, bromine is a liquid and iodine is a solid.

• Seven valence electrons

Properties of the Major Groups

8A noble gases• Argon discovered in 1894 - eluded discoverty

to due lack of reactivity!

• aka ‘rare gases’, make up 1% of atmosphere.

• relatively unreactive - inert, stable (so good for lights!)

• Have full valence shells - all have eight valence electrons except helium (full with two)