Answer : A Lewis structure is a graphical representation of the distribution of electrons around atoms. Mainly it illustrates the lone pairs of electrons present in molecules. They are also known as Lewis dot diagrams and mainly used for simple way to represent the configuration of atoms within a molecule.
The halogens are the five non-metallic elements found in group 7A of the modern periodic table. The term "halogen" stands for "salt-former" and compounds which contains halogens are called as "salts" as they produce salts when it reacts with metals.
All halogens are supposed to have 7 electrons in their outermost shells.
When a diatomic structure is formed by two elements of halogens, one electron from each halogen combines to form bonds between them.
Hot air balloons have hot air inside them, which is less dense as the air around it. Thus it rises. A cold air balloon would sink because the air would be more dense than the air around it. Also, the balloon’s volume would vary in size depending on the weight of the balloon.