S.6 Chem Periodicity Notes Caltec S.6

CHEMISTRY NOTES Instructions. - READ AND WRITE THESE NOTES PLEASE - Equations and Diagrams will be elaborated during lessons. PERIODI CITY The per iodic table of el ements is the cha rt in which the known chemical elements are listed inorder of increasing atomic number with chemically similar elements occupying the same vertical c olumns. The periodic table consists of two m ajor divis ions I) periods: this is the horizontal arrangement of elements. There are 7 periods. ii) groups: this is the ver tical arrangement of element s There are 8 groups. Groups 1 to V11 are sub divided into A and B thus we can talk of I 've and IV B. Group V11 1 ha s 3 columns which include the groups containing iron nickel and cobalt respectively The Noble gases belong to group O The periodic table is as shown on the next page Leave one page for the periodic table It should be noted that there is no special resembla nce between the chemistry of the subgroups A and B eg IV A elements are not related to IV B elements except perhaps their valencies The division into s ubgroups is merely a method used by Mendeleev in his original periodic table For simplicity we shall be m erely referring to 1 , 11,111 etc On analysis, it is observed that the elements within the same outer electronic configuration and similar c hemical properties. However no element is exactly the same as another Elements within the same group show; Similar p roperties due to their similar outer electronic configuration A gradual change in properties down the group due to gradual change in electronegativity down the group However the first member in an y group usually shows ano malous behavior due to high electr onegativity small …