Question

Elements of IA group give colour in bunsen burner flame because of:
A) Low ionization potential
B) Low melting point
C) Softness
D) All of these

Answer 1

Hint: Think about the possible factors that can affect the chemical and physical properties of the element and also the factor given in the option for given elements. The elements in a group or a period are denoted by a specific number which shows its reactivity.

Complete step by step answer:
1) First of all we will understand the factor which has to make the elements have similar chemical properties and physical properties.
2) The chemical properties and physical properties of an element depends on the number of valence shell electrons. The valence electrons are the electrons that participate in the chemical bond formation with other elements.
3) The elements that are arranged in the periodic table according to the elements which have the same number of valence electrons are grouped together in column/groups.
4) Now let us see an example of the halogen group. The halogens group is Group VII which has elements such as fluorine, chlorine, bromine, iodine, and astatine. All these elements have seven electrons in their valence shell and hence they show similar chemical properties and physical properties. This factor also applies to every group and column in the periodic table.
Therefore, Elements in the same column/group of the periodic table have similar chemical properties because their atoms have the same number of valence electrons which shows option C as the correct choice.

Note:
In the case of the physical properties of elements such as melting point, boiling point depends on the valence shell to a lesser extent and it also depends on the element's atomic interactions present between the atoms of the element which also shows similarity along with the group.