Question

The total number of elements in VII A group of the periodic table is:
A.3
B.5
C.7
D.9

Answer 1

Hint: There are eighteen vertical columns known as groups in the modern period which are arranged from left to right and seven horizontal rows which are known as periods. Moreover, the elements in VII A group are known as halogens.

Complete step by step answer:
- Earlier the scientists assumed that the properties of elements are periodic functions of their atomic masses. So, on the basis of this assumption, Mendeleev placed 63 elements in a vertical column called as groups and in horizontal rows known as periods. But this method was rejected because it could not explain the position of certain elements.
-After that a scientist named Henry Moseley removed these defects and put forward the modern periodic table. He further stated that the properties of elements are periodic functions of their atomic number.
-Now, let’s talk about group 17 or VII A elements. These elements are Fluorine, Chlorine, Bromine, Iodine and Astatine. These are generally known as halogens. The word halogen is a Greek word which means salt producer. These are known as salt producers because chlorine, bromine and iodine are highly electronegative in nature and form anions that constitute the anionic part of salts found in the seawater whereas the last element i.e. astatine is radioactive in nature.
-Moreover, after the alkali group, the halogen family constitutes the most homogeneous group in the modern periodic table.
Therefore, there are 5 elements present in group VII A.

Hence, option B is correct.

Note:
Molecules of all the halogens are diatomic. This means that their molecules exist with two atoms each. Moreover they are highly reactive and can gain electrons by reacting with atoms of other elements. They are poor conductors of heat and electricity and have low melting and boiling points.