Question

Find the correct statement:
(A) all the three types of valencies are observed by the representative elements.
(B) only two types of valencies are observed in case of representative elements.
(C) all representative elements show ionic valency.
(D) none of these.

Answer 1

Think about the representative elements in the periodic table. Find out what valency is and how many types of valencies are there. Take a look at the representative elements and figure out how many types of valencies do they possess and then mark the most suitable option.

Complete answer:
- Representative elements are the elements which are present in the first series of each group which represent the elements present in that particular group. For example, Hydrogen, Helium, Lithium, Beryllium, Boron, Carbon, Oxygen, Nitrogen and Fluorine are some representative elements.
- Valency is the number of electrons which need to either be gained or lost by an atom to gain stability by attaining noble gas configuration.
- There are three types of valencies: Primary or classical, Secondary or coordinate and Tertiary or non-classical valency.
- Primary valency is seen in ionic and covalent compounds i.e. ionic and covalent bonding.
- Secondary valency is seen in coordination complexes i.e. coordinate bonding.
- Tertiary valency is a special type of valency seen in metal carbonyls .i.e. synergic bonding.
- The representative elements exhibit all the three types of valencies.

Therefore, the correct option is option (A).

Note:
Remember representative elements are the elements present in the periodic table which represent the elements present in that particular group. Like boron family, carbon family, nitrogen family, halogens, alkali metals, lanthanides, actinides, transition metals, and so on.