Question

What is unique about each element of the periodic table?

Answer 1

Hint: We have to remember that the electronic configuration of the elements helps in determining its physical property and chemical property. The number of valence electrons also help in determining the physical properties of the elements.

Complete answer:
As we know that the unique properties about each element is that it has a unique value of protons and neutrons. These numbers of protons and neutrons decide the atomic number and the mass number of the elements.
We need to know that the valence electrons are those which are present in the outermost shell of the atom. The number of valence shells help in determining the group number.
Number of protons is equal to the number of electrons. Number of protons is equal to the atomic number of the element.
We also remember that the number of neutrons is equal to the subtraction of atomic number from mass number.
Thus, the unique property is the number of protons and neutrons.

Additional information:
We need to know that the modern periodic table is given by Henry Mosely.
Modern periodic table is based on modern periodic law. According to modern periodic law, it states that the physical and chemical properties are periodic functions of their atomic numbers. It is arranged on the basis of increasing atomic number. Periodic table is divided into groups and periods.

Note:
We have to remember that the atomic numbers and mass number of the elements should be kept in mind and formulas should also be remembered for proper calculation of neutrons and protons.
Number of Protons= Atomic number of the element
Number of Protons=Number of electrons
Number of neutrons=Mass number-Atomic number