Modern Periodic Law

Modern Periodic Law:

The Modern Periodic Law states, “The physical and chemical properties of elements are periodic functions of their atomic numbers.”

Atomic number (Z) represents the number of protons and is a fundamental property of elements.
Henry Moseley (1913) proved through X-ray experiments that elements should be arranged by atomic number, not atomic mass.
This led to the modification of Mendeleev’s periodic table, improving the classification of elements.
The modern periodic table is now based on atomic number, explaining element properties, periodic trends, and chemical behaviour more accurately.

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Modern periodic law states that the physical and chemical properties of elements are the periodic functions of their ______.

Give a reason for the following:

Properties of elements are periodic functions of their atomic numbers and not atomic weights.

Group in the modern periodic table	Families
1	______
______	Transition metals
______	Boron family
15	______
17	______

State whether true or false. If false, correct the statement.

Newlands’ periodic table is based on atomic masses of elements and modern periodic table is based on atomic number of elements.

The atomic number of an element is more important to the chemist than its relative atomic mass. Why?

In Modern Periodic Table the number of columns and periods are respectively _______ and _______.

State modern periodic law.

Relative atomic mass of a light element up to calcium is approximately ______ its atomic number.