give the pictographic symbols of elements as well as definition valence and formulae of radicals with tables of examples
Answers
Explanation:
VALENCY - DEFINITION
Valency is defined as the combining capacity of an element with another element. It can be used to find out how the atoms of an element will combine with the atoms of another element to form a chemical compound. e.g the valency of oxygen is 2, carbon is 4 etc.
RULES FOR WRITING CHEMICAL FORMULA - DEFINITION
1. Write the symbols side by side, basic radical is written first and then acidic radical.
2. Write the valency of each atom on top of its symbol.
3. Divide the valency numbers by their highest common factor. Ignore the symbols of radicals. Interchange the valencies of the radicals.
4. Write the interchanged valency numbers to the lower right of the radicals. If the radical is a group of atoms and has a valency more than one, enclose it within brackets.
FORMULA OF VALENCY - FORMULA
The steps to calculate the valency are:
1. Write the electronic configuration of an element.
2. If the outermost shell has less than or equal to four electrons then the valency is the number of outermost electrons.
3. If the outermost shell has more than four electrons then the valency is 8-(the number of outermost electrons).
VALENCY FROM THE FORMULA - DEFINITION
Valency is the combining capacity of one element with the other element.
1. Atom of chlorine combines with 1 atom of hydrogen to form HCl (hydrogen chloride) The valency of chlorine is thus 1 .
2. 1 atom of carbon combines with 4 atoms of hydrogen to form CH
4
(methane). The valency of carbon is thus 4.
CALCULATE VALENCY OF AN ATOM - DEFINITION
The valency of hydrogen and all metals is positive. The valency of non- metals is negative. The valency of a molecule is zero.
Valency is calculated by calculating number of electrons present in outermost orbitals of atom of element.
For example : Valency of Nitrogen is 3 because outermost orbital contain 3 electron.