Na, Mg, and Al are the elements of the 3rd period of the Modern Periodic Table having group numbers 1, 2, and 3 respectively. Which one of these elements has the highest valency (b) largest atomic radius and (c) maximum chemical reactivity? Justify your answer stating the reason for each.

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Solution

Step 1:
Modern periodic table:
The modern periodic table consists of 118 elements in total. Out of 118 elements, 94 elements occurred naturally whereas the rest of the elements were synthesized in the laboratory.
Step 2:
Explanation:
Sodium (Na) Z = 11
Magnesium (Mg) Z = 12
Aluminium (Al) Z = 13
(a)The element having the highest valency is Aluminum (Al), as it has 3 valence electrons. It will lose all its valence electrons.
(b)The element with the largest atomic radius is Sodium (Na) as left to right atomic radius decreases due to an increase in nuclear charge.
(c) The element with maximum chemical reactivity is Sodium (Na) as a metallic character because it is the most electropositive element. As the metallic character increases for an element increases, the ease with which an electron is removed from the atom increases. Therefore, its chemical reactivity increases.

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