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Which one of the following statements is false?

(a) The first ionization energy of bromine is larger than that of calcium

(b) The first ionization energy of barium is smaller than that of magnesium

(c) In a given row in the periodic table, the alkali metal always has the largest first ionization energy

(d) The melting points of the alkali metals decrease as their atomic weights increase

(e) The second ionization energy of an element is always greater than the first ionization energy.

1 Answer

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Final answer:

The false statement is (c) that alkali metals have the largest first ionization energy in a row. Ionization energy increases from left to right across a period. Therefore, option (c) is the false statement.

Step-by-step explanation:

The statement that is false is (c) In a given row in the periodic table, the alkali metal always has the largest first ionization energy. This is incorrect because first ionization energy typically increases across a period from left to right, meaning that the alkali metals (which are on the left side of a period) have the lowest ionization energies, not the highest.

As for the other statements: (a) The first ionization energy of bromine is indeed larger than that of calcium, since calcium is an alkaline earth metal and bromine is a non-metal further to the right on the same period; (b) Barium, being further down on the periodic table than magnesium.

It has a smaller first ionization energy since ionization energy decreases down a group; and (e) The second ionization energy of an element is indeed always greater than the first, because it is more difficult to remove an electron from a positively charged ion than from a neutral atom.

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