Question

The physical properties of elements changes according to________________
A.Classification of elements in groups and periods
B.Classification of elements in groups
C.Classification of elements in periods
D.None of these

Answer 1

Hint: The classification of elements according to the modern periodic table depends on two properties, that is, physical and chemical properties. The elements having similar properties are arranged in respective periods or groups.

Complete step by step answer:
To get the answer for this question, let us first look at some of the physical properties. Finding the trends in these properties will help us to know if it depends on the group or the period.Below we can see a few physical properties depending upon their trend we can conclude our answer.Let us look at the first property:
1)Atomic radius
Atomic radius is the distance from the center of the nucleus to the outermost shell of electrons. It is seen that atomic radius decreases as we go left to right across the period and it increases from top to bottom within a group as atomic number increases within a group. This observation shows that elements are classified and placed within a group and period as per their increase and decrease in atomic radii.
2)Ionization energy
It is the energy required to remove the electron from the outermost orbital. It is observed that it increases across the period and decreases down the group same as the atomic radii.
3)Electronegativity
Electron attraction ability of an atom is called electronegativity. It is seen that from left to right electronegativity increases and from top to bottom within a group it decreases.So, it directly depends on atomic radii which in turn depends on atomic number.
It can be seen that the physical properties are interrelated and depend upon the number of electrons in the outermost shell(valence electrons) and hence varies with the change in atomic number across the period and within the group. Thus, we can say that option ‘A’ is the correct answer, that is, the physical properties of elements change according to their classification within a group and across the periods.

Hence option A is correct.

Note:
Not all properties show similar trends, some properties like boiling and melting point, metallic property etc. depend upon individual groups that we are talking about. Study the individual property to draw conclusions about their behavior across the period or within a group.