Which has the largest atomic radius calcium bromide barium and astatine

Answer : Barium has the largest atomic radius.

Explanation :

The periodic trend observed with respect to atomic radius is explained below.

Across a period : As we move from left towards right across a period, atomic radius decreases.

This happens because as we move towards right, an extra electron gets added to the same shell. But as we move towards right, the effective nuclear increases. As a result nucleus pulls the outer electrons more strongly which results in shrinking of the atom.

Down the group : As we move down the group, the atomic radius increases.

Because as we move down, an extra shell gets added to the atom. Due to this size of the atom increases.

If we look at the positions of the given elements , we see that Calcium and Bromine are present in fourth period whereas Barium and Astatine are present in sixth period.

According to periodic trend observed for group, Barium and Astatine would have larger atomic radii than Calcium and Bromine.

If we apply periodic trend observed across a period, we can say that Barium is larger than Astatine because it is more towards left .

Therefore the atom with largest radius is Barium.

answer: - 3.) the oxidation state of nitrogen in no changes from +2 to 0, and the oxidation state of carbon in co changes from +2 to +4 as the reaction proceeds.

solution: - as per the rules, oxidation number of oxygen in its compounds is -2. the sum of oxidation numbers of all the elements of a molecule or compound is zero.

also, the oxidation number in elemental form is zero.

in no, the oxidation number of o is -2 so the oxidation number of n is +2 so that the sum is zero.

similarly, the oxidation number of c in co is +2 and o is -2.

on product side the oxidation number of n is 0 as it is in the elemental form() .

oxidation number of c in carbon dioxide is +4 as there are two oxygen in it and we know that each oxygen is -2.

so, oxidation number of n is changing from +2 to 0 and the oxidation number of c is changing from +2 to +4.

since nitrogen is reduced and hence no is acting as an oxidizing agent. carbon is oxidized and so co is acting as a reducing agent.

so, the right choice is number 3.)the oxidation state of nitrogen in no changes from +2 to 0, and the oxidation state of carbon in co changes from +2 to +4 as the reaction proceeds.

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