Secondary Catalogue

Series: Periodic Classification of Elements


Characteristic of Periods: Nature of Oxides

Characteristic of Periods: Nature of Oxides

The oxides of metals are basic, while those of non-metals are acidic. On moving from the left to the right in a period, the metallic character of the elements decreases, while the non-metallic character increases. The nature of the oxides of...Show More
Characteristics of Groups: Atomic Size

Characteristics of Groups: Atomic Size

The atomic size of an atom is the distance between the centre of its nucleus and its outermost electron shell. As we move down in a group, the atomic size of the elements increases gradually.
Characteristics of Groups: Chemical Reactivity and Nature of Oxides

Characteristics of Groups: Chemical Reactivity and Nature of Oxides

The chemical reactivity of metals increases from the top to the bottom in a group, while the chemical reactivity of non - metals decreases as we move down in the group. On moving down in a group of the Periodic Table, there is no change in the...Show More
Characteristics of Groups: Valence Electrons and Valency

Characteristics of Groups: Valence Electrons and Valency

The groups in the Periodic Table are arranged vertically. There are 18 groups in the Periodic Table. All the elements in one group have the same electronic configuration and hence the same number of valence electrons and the same valency.
Characteristics of Periods: Atomic Size and Metallic Character

Characteristics of Periods: Atomic Size and Metallic Character

The atomic size of an atom is the distance between the centre of its nucleus and its outermost electron shell. In the Periodic Table, on moving from the left to the right in a period, the atomic size and metallic character of the atoms decreases...Show More
Characteristics of Periods: Chemical Reactivity

Characteristics of Periods: Chemical Reactivity

The chemical reactivity of an element depends upon the position of the element in the Periodic Table and the electronic configuration of the element. On moving from the left to the right in a period, the chemical reactivity of the elements first...Show More
Characteristics of Periods: Valence Electrons

Characteristics of Periods: Valence Electrons

The horizontal rows of the elements in a Periodic Table are known as periods. There are seven periods in the Periodic Table. On moving from the left to the right in a period, the number of valence electrons in the elements increases from one to...Show More
Characteristics of Periods: Valency

Characteristics of Periods: Valency

The valency of an element is determined by the number of valence electrons present in its atom. The valency of the element is calculated by the number of electrons lost or gained by its atom to achieve the nearest inert gas electron configuration.
Mendeleev's Periodic Table

Mendeleev's Periodic Table

Mendeleev’s Periodic Law states that the properties of elements are a periodic function of their atomic masses. The limitations of Mendeleev’s classification were that it could not explain the position of isotopes and the correct position was...Show More
Modern Periodic Law

Modern Periodic Law

The modern periodic law states that properties of elements are the periodic function of their atomic numbers. The atomic number is equal to the number of electrons; it helps in arranging elements according to their electronic configuration, which...Show More
The Modern Periodic Table

The Modern Periodic Table

The elements in the Periodic Table are roughly divided into metals, metalloids and non-metals. There are seven periods in the Periodic Table. The vertical columns in a Periodic Table are called groups and there are 18 groups in the Periodic Table.