Correct the statements:
i) elements in the same period have equal valency
ii) valency depeands upon the number of shells in an atom
iii) copper and zinc are representative elements
iii) transition elements are places at the extreme right of the periodic table
The corrected statements are as follows:
i) Elements in the same group have equal valency.
ii) Valency depends upon the number of electrons in the outermost shell in an atom.
iii) Copper and zinc are transition elements.
iii) Transition elements are placed at the middle of the periodic table.
Brief explanation: i) and ii) Elements in the same period have same outermost shell while elements in the same group have the same number of electrons in their outermost hell and hence, same valency.
iii) Copper and zinc have incomplete d-orbitals in their elemental state or in their dominant oxidation states and hence called transition elements.
iv) Transition elements (or d-block elements) are placed at the middle of the periodic table, in between the two blocks of representative elements (i.e. s-block and p-block).