Question

Which of the following statements is false?

Electron affinity is a measure of the energy evolved when a gaseous atom gains an electron

Anions are smaller than the parent atoms from which they are derived

Ionization energies decrease as the atomic radius increases

For isoelectronic cations, the higher the charge, the smaller the ion

Cations are smaller than the parent atoms from which they are derived

Answer 1

a)

we know that

electron affinity is the energy released when an electron is added to gaseous atom

so the given statement is correct

b)

now

consider a parent atom

now an electron is added to it

it becomes an anion

the added electron created repulsions with existing electrons and the size will increase

so the anion is larger than the parent atom

so the given statement is false

e)

similarly a cation is formed by the removal of an electron

the nucleus will attract the remaining electron with an increased force

so the size decreases

so cations are smaller than the parent atoms

so

the given statement is true

c) given

atomic radius increase

we know that

as the atomic radius increases , the valence electrons are loosely bound to the nucleus

so they can be eaily removed

as a result less energy is required

so ionization energy decreases as the atomic radius increases

the given statement is true

d) isoelectronic cations have same number of electrons

consider

A+1 , B+2 and C+3 all are isoelectronic

as the charge increases, it means more electrons are removed

as more electrons are removed , the nucleus will strongly attract the remaining electrons

so the size decreases

so for isoelectronic cations

higher the charge, smaller the ion

the given statement is true

so

the false statement is b) Anions are smaller than the parent atoms from which they are derived