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The Periodic Table

The Periodic Table. The periodic table of the elements was originally developed, in the form that we are familiar with, by a Russian chemist named DMITRI MENDELEEV . His table was based on observations of THE CHEMICAL AND PHYSICAL PROPERTIES of the elements known at the time. .

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The Periodic Table

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  1. The Periodic Table

  2. The periodic table of the elements was originally developed, in the form that we are familiar with, by a Russian chemist named DMITRI MENDELEEV. His table was based on observations of THE CHEMICAL AND PHYSICAL PROPERTIES of the elements known at the time.

  3. Mendeleev noticed that these PROPERTIES REPEATED THEMSELVESover and over again when the elements were ARRANGED IN ORDER OF INCREASING ATOMIC NUMBERS. It was this repetition that led to the choice of the name "PERIODIC".

  4. Metals Elements that tend to LOSE ELECTRONS and become POSITIVELY CHARGED IONS are found on the LEFT SIDE of the periodic table. These elements are METALSand have the characteristic properties of metals: they are SHINY, SOLID AT ROOM TEMPERATURE, MALLEABLE, GOOD CONDUCTORS OF HEAT AND ELECTRICITY, AND HAVE HIGH MELTING POINTS.

  5. Non - Metals Elements that tend to GAIN ELECTRONS and become NEGATIVELY CHARGED IONS are found on the RIGHT SIDE of the periodic table. These elements are NON-METALS and have the characteristic properties of non-metals: they are DULL, LIQUID OR GAS AT ROOM TEMPERATURE, BRITTLE AS SOLIDS, POOR CONDUCTORS OF HEAT AND ELECTRICITY, AND HAVE LOW MELTING POINTS.

  6. Metalloids There is no clear-cut division between the two types of elements but the "STAIR‑STEP" LINE, toward the right hand side of the table, SEPARATESthe metallic elements from the non-metallic elements. ELEMENTS NEAR TO THIS LINE may have properties of both types of elements and are called METALLOIDS.

  7. Families & Groups The columns in the periodic table organize the elements into groups or FAMILIES BASED ON THE NUMBER OF ELECTRONS IN THE OUTER SHELL. Each group is identified by a Roman Numeral and may, or may not, use a letter of the alphabet. Groups of elements have SIMILAR CHEMICAL AND PHYSICAL PROPERTIEScaused by their similar electron arrangements.

  8. In groups of METALS, THE MOST REACTIVE ELEMENTis at the BOTTOM OF THE FAMILY. In groups of NON‑METALS the MOST REACTIVE ELEMENT is at the top of the family. The elements of one family, group VIII, also called the INERT GASES or the NOBLE GASES, are almost completely NON-REACTIVE because they have the STABLE OCTET electron arrangement.

  9. Periods These are the HORIZONTAL ROWS across the table. In a period there is a gradual change from metals to non-metals as the atomic number increases and as the number of electrons in the outside shell increases. A period always STARTS WITH AN ELEMENT HAVING ONE ELECTRON in the outermost shell and ends with 8 electrons in this outer shell, period 1 being the only exception

  10. Element Video What is the Periodic Table

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