Question

Name the most reactive element in Group VIIA of the periodic table.

Answer 1

Hint: Group VIIA is the group of the periodic table which contains halogens.
Now that you have this information, try thinking of all the trends in chemical properties while moving from top to bottom in a group.

Complete step-by-step answer:
To help us answer this question, let us first go through the properties of halogens and then with the trend of chemical properties in the group, determine the most reactive of them all.
The Group 7A elements have seven valence electrons in their highest-energy orbitals ($ns^2np^5$). This is one electron away from having a full octet of eight electrons, so these elements tend to form anions having -1 charges, known as halides: fluoride, F-; chloride, Cl-, bromide, Br-, and iodide, I-. In combination with other non-metals, the halogens form compounds through covalent bonding.
The halogens are extremely reactive, and are not found naturally in their elemental forms. They are usually found in combination with various metals in minerals, or in combination with other non-metals in molecular compounds.
The halogens also form compounds with carbon easily; organic molecules containing carbon are often known as alkyl halides, or organohalides, and have many different household and industrial uses.
An extremely chemically electronegative gas which is toxic in nature with atoms of the smallest size when compared to any other halogen, Fluorine is the most reactive element present in Group VIIA and the most reactive non-metal present in the periodic table.

NOTE: It is extremely important to be familiar with the trends of electronegativity and size in the halogen group to be able to answer this question. Along with this knowledge, it is also extremely important to remember the chemical properties of Fluorine, a lot of which differ greatly from other halogen elements.