Wrong grouping in modern periodic table
Answers
. in a period of the periodic table, the number of valence electrons increases as atomic number increases. As a result, elements change from metal to metalloid to non-metal to noble gas.
⋅ Atomic size is a periodic property. As atomic number increases in a period, atomic radius decreases. As atomic number increases in a group, atomic radius increases.
⋅ Positive ions have smaller atomic radii than the neutral atoms from which they derive. Negative ions have larger atomic radii than their neutral atoms.
⋅ Positive ions in the same group increase in size down the group.
⋅ In a group, each element has the same number of valence electrons. As a result, the elements in a group show similar chemical behaviour.
⋅ Metallic character decreases from left to right in a period because of the increase in the effective nuclear charge.
⋅ Non-metallic character increase from left to right in a period because of increase in effective nuclear charge. Non-metallic character decreases down the group because of increase in the size of the atom.
Following are the defects:
Position of hydrogen still dicey. It is not fixed till now.
Position of lanthanides and actinides has not been given inside the main body of periodic table
It does not reflect the exact distribution of electrons of some of transition and inner transition elements.