Question

periodic
1. Periodic properties
* Modem periodic law
Properties of elements are
function of their atomic number
* Sailent features of modem periode
tabler
18. vertical colestos called greeyat
» Horizontal rows called percode
blocks
S
д groupe
1 and 2​

Answer 1

Answer:

Pokimon fean

Explanation:

Answer 2

1. Periodic properties of elements-

The basic law governing modern periodic table states that the properties of elements are periodic functions of their atomic number. These properties reappear at regular intervals or follow a particular trend at regular intervals. This phenomenon is known as the periodicity of elements.

The periodic properties of elements occur due to the recurrence of similar electronic configuration that is having the same number of electrons in the outermost orbit. In a particular group, the number of valence electrons remains the same. On the other hand, the number of valence electrons increases, as we move from left to right across a period. The chemical property of an element depends on the number of electrons in the valence shell.

2. The modern periodic law states that the physical and chemical properties of the elements are the periodic functions of their atomic numbers. Scientists arranged elements in increasing order of their atomic numbers from left to right across each row.

3. These properties include color, density, melting point, boiling point, and thermal and electrical conductivity. While some of these properties are due chiefly to the electronic structure of the element, others are more closely related to properties of the nucleus, e.g., mass number.

4. The atomic number uniquely identifies a chemical element. It is identical to the charge number of the nucleus. In an uncharged atom, the atomic number is also equal to the number of electrons. The sum of the atomic number Z and the number of neutrons N gives the mass number A of an atom.

5. The main features of modern periodic table-

• Elements are arranged in the increasing order of atomic numbers.

• Elements in the modern periodic table are arranged in 7 periods and 18 groups.

• Horizontal rows are called periods and vertical columns are called groups.

6. The elements are arranged in seven horizontal rows, called periods or series, and 18 vertical columns, called groups.

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