Which of the sets of elements are not in order of increasing force of attraction on the outermost electron in atoms of that element? Ba < Sr < Ca
Al < P < Cl
F < Cl < Br
Mo < Pd < Sn

The elements that are not arranged in their increasing force of attraction base on the outermost electron present in their atoms is D:

Mo < Pd < Sn.

Therefore , option D is correct.

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The set of elements that are not arranged in the order of increasing ionization energy is Mo < Pd < Sn

Explanation:

The force of attraction on the outermost electron of an element can be described by the ionization energy of the element which decreases down a group and increases across a period

1) The given elements Ba, Sr, Ca, are group 2 elements arranged in the order from bottom up, which gives an increasing ionization energy, therefore;

Ba < Sr < Ca is arranged in increasing ionization energy, and therefore, increasing force of attraction of the outermost electron in atoms of the elements

Similarly, Al < P < Cl and Mo < Pd < Sn, are arranged in order of increasing ionization energy

However F < Cl < Br which are arranged from top down of elements in period 17 are arranged in the order of decreasing ionization energy, and therefore, decreasing force of attraction of the outermost electron in atoms of the elements.

a:

by the combination of an unlimited number of elements