1. What is meant by the term 'symbol. Give the qualitative and quantitative meaning of the term 'symbol".
2. Name three metals whose symbols are derived from:
a) the first letter of the name of the element, b] from their latin names.
3. Explain the meaning of the term 'valency'.
State why the valency of the metal potassium is +1 and of the non-metal chlorine is -1.
4. What is meant by the term 'variable valency'. Give a reason why silver exhibits a valency of +1 and +2.
5. Give examples of eight metals which show variable valency. State the valency of sulphur in : a] SO2, b] S03.
Answers
Answer:
1.Symbol- It is the short form that stands for the atom of a specific element. Qualitative meaning -C is the symbol of atom of element carbon. ... No two elements can have the same symbol. Quantitative meaning-A symbol represents quantity of the element ,i.e atomic mass of element.
3. In chemistry, the valence or valency of an element is a measure of its combining power with other atoms when it forms chemical compounds or molecules.
4. The electrons which are present in an atom's outermost shell are called valence electrons. So one or more electrons from the core's outermost shell may also be lost after the removal of valence electrons.
Silver has electronic configuration [Kr] 4d^10 5s^1.
- Being a d-block element, it has ability to show variable oxidation states.
- Usually silver loses one electron from 5s to exhibit valency +1.
- At other times, silver loses one electron from 5s & 4d each to show valency +2.
5.EIGHT METALS WHICH SHOW VARIABLE VALENCY ARE :
IRON
COPPER
MERCURY
SILVER
TIN
LEAD
PLATINUM
GOLD
MANGANESE
so sulfur atom has valency of IV in SO2 molecule (There is delocated electron but we accept that it is 4, because of electron configuration of sulfur), and both oxygen atoms has a valency of II
In SO3 molecule, sulfur atom has a valency of VI, and all oxygen atoms II
Generally you accept valency of Oxygen atoms II(except CO and H3O+) and calculate other atoms valency based on that. Also first group metals and hidrogen always I, second group always II, Fluorine always I and so on
Explanation:
Answer:
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