vacancy of this element is 3. This element is nitrogen. Vacancy is the combining capacity of an element.

Valency of an Element with Z=7

Element Name: The element with atomic number (Z) 7 is nitrogen.

Valency: Valency is the combining capacity of an element, which determines the number of electrons an atom can gain, lose, or share to attain a stable electron configuration. It is a measure of how many chemical bonds an atom can form with other atoms.

Definition of Valency: Valency can be defined as the number of electrons an atom needs to gain, lose, or share to achieve a stable electron configuration, usually that of a noble gas.

Determination of Valency: The valency of an element can be determined based on its position in the periodic table and the number of valence electrons it possesses.

Valency of Nitrogen:
1. Nitrogen belongs to Group 15 (Group V) of the periodic table.
2. Elements in Group 15 have five valence electrons.
3. The valency of nitrogen can be determined by the difference between its valence electrons (5) and the octet rule (8).
4. Nitrogen has a valency of 3 since it requires three more electrons to complete its octet and achieve stability.
5. Nitrogen can either gain three electrons or share three electrons to achieve a stable electron configuration.

Explanation:
The valency of an element indicates its combining capacity and is determined by the number of valence electrons an atom possesses. Valence electrons are the outermost electrons in an atom's electron configuration.

In the case of nitrogen, it has an atomic number (Z) of 7, which means it has 7 electrons. The electron configuration of nitrogen is 2-5, which indicates that it has two electrons in the first energy level and five valence electrons in the second energy level.

To achieve a stable electron configuration, nitrogen needs three more electrons to complete its octet. By gaining three electrons or sharing three electrons with other atoms, nitrogen can attain stability. Hence, the valency of nitrogen is 3.

Valency plays a crucial role in chemical bonding and determines the type and number of bonds an atom can form with other atoms. It helps in understanding the reactivity and behavior of elements in chemical reactions.

In conclusion, the element with atomic number (Z) 7 is nitrogen, and its valency is 3. Valency represents the combining capacity of an element and is determined by the number of valence electrons an atom possesses.