Grouping Elements in the Periodic Table

This is based on the filling of electrons in orbitals around the nucleus. The s orbital has two electrons (one pair), the p orbital holds six electrons (three pairs), the d orbital fits ten electrons (five pairs), and the f orbital can hold 14 electrons (seven pairs). A simple way to remember is one, three, five, and seven electron pairs, for the s, p, d, and f orbitals. 

Because the outer orbitals and the number of electrons in that orbit determines the chemical differences, it is logical to order the periodic table according to blocks associated with a particular orbit. Hence there are s-block elements, p-block, and so on. 

X XXX Synthetic Liquids or Solids Gases Alkali Alkali Transition Other Other 

Elements in the same block share some similarities, but the similarities are clearer when the elements are ordered according to groups. 

Valence is a term that signifies the power of the atoms to form chemical bond. It s Latin for be strong.  

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Examine the main-group elements in the periodic table. Imagine how their size might change as you move down a group or across a period. What knowledge and reasoning can you use to infer the sizes of the atoms ... 

Calculate the percentage of main group elements in the periodic table. 

Representative Elements. The A group elements in the periodic table are called representative elements. Their last electron is assigned to an outer shell s or p orbital. These elements show distinct and fairly regular variations in their properties with changes in atomic number. 

Combustion reaction The rapid oxidation-reduction reaction of an oxidizable substance with oxygen in a highly exothermic reaction, usually with a visible flame. d-Transition elements (metals) The B group elements in the periodic table sometimes called simply transition elements. Effective nuclear diarge (Ze The nuclear charge experienced by the outermost electrons of an atom the actual nuclear charge minus the effects of shielding due to inner shell electrons. 

Each column within the main group elements in the periodic table is labeled as a family or group of elements. The elements within a group usually have similar chemical properties. 

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