Arrange the elements in decreasing order of first ionization energy.
rank from highest to lowest first ionization energy. to rank items as equivalent, overlap them.

in, ge, se, cs

part b:
arrange the elements in order of decreasing first ionization energy. rank from highest to lowest first ionization energy. to rank items as equivalent, overlap them.

element x (radius (pm): 110)
element y (radius (pm): 199)
element z (radius (pm): 257)

Here, we are required to arrange elements in decreasing order of first ionization energy.

(a) Se > Ge > In > Cs

(b) element x > element y > element z

The ionization energy of an atom is simply defined as the amount of energy required to completely pull out an electron from the outermost shell of the atom.

As such, the larger the atomic radius, the lower the first ionization energy and vice versa.

In the periodic table, the atomic radius of elements increases down a group and decreases across a period.

The position of the elements given in the periodic table is as follows;

(a) Ultimately, the arrangement of the elements in decreasing order of first ionization energy from highest to lowest is;

Se > Ge > In > Cs

(b) As we know, the first ionization energy of atoms decreases as there atomic radius increases and vice versa.

The elements and their atomic radius are as follows;

Therefore, to rank the elements in order of decreasing first ionization energy; we have;

element x > element y > element z

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fe 55.85 g/mol and h2o 18.02 g/mol.