(a) What is meant by periodicity in properties of elements with reference to the periodic table?
(b) Why do all the elements of the same group have similar properties?
(c) How will the tendency to gain electrons change as we go from left to right across a period? Why?
Answers
a) In general elements directly above and below an element in the periodic table will react with other elements similarly. For example the sodium in sodium chloride can be replaced with lithium, to form lithium chloride, or potassium, to form potassium chloride. Or you could replace the chlorine with fluorine to make sodium fluoride or bromine to make sodium bromide. This is because these elements have the same number of electrons on the outer shell, called the valence electrons.
The periodicity was discovered long before the reason behind it
b):- In general elements directly above and below an element in the periodic table will react with other elements similarly. For example the sodium in sodium chloride can be replaced with lithium, to form lithium chloride, or potassium, to form potassium chloride. Or you could replace the chlorine with fluorine to make sodium fluoride or bromine to make sodium bromide. This is because these elements have the same number of electrons on the outer shell, called the valence electrons.
The periodicity was discovered long before the reason behind it
The tendency to gain electrons decreases as we go down the 16th group this happens because as we go down the atomic size of the element increases and as a result the metallic character increases and hence the element becomes more eligible in losing electrons.
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