For the elements with large atomic numbers, we prefer to write the electronic configuration taking the help of inert elements near to that element. And for this, we may need knowledge about every element of the periodic table which is quite difficult.

So in this context, we take the help of half-filled and full filled orbitals. I mean the electronic configuration is done by fulfilling the electrons in the orbitals either fully or half to get a stable configuration. Since f orbital can hold 14...

Ans: Isoelectronic species are theatoms or ions that have same number of electrons.

Ans: Since alkaline earth metal and noble gases are stable elements due to having full or half filled electronic configuration. So, they can't easily gain any electron. Therefore their electron affinity are almost equivalent to zero.

Ans: Modern periodic law states that, " The physical and chemical properties of elements are the periodic function of their atomic numbers."

Ans: Fluorine has very small atomic size so there is more inter electronic repulsion. But chlorine has larger size and repulsion between the electron of chlorine is very less. Hence, it can easily gain electron but fluorine can't. So electron gain enthalpy of fluorine is unexpectedly less than of chlorine.

Ans: The size of anion is larger than the size of parent atom because anions are formed due to gain of electrons. When the electrons increases, there are still the same number of protons. This causes the electrons to not be bound tightly to the nucleus like earlier and results in an increase atomic size.

Ans: Size of cation is smaller than the size of parent atom because as parent atom loses electron and form cation where number of proton becomes more than number of electron and attractive force increases so radius decreases.

Ans:As we know the elements having half-filled and full filled electronic configuration are stable and they need more energy to move the electron and have higher ionization energy. So, (a) and (c) have higher ionization energy because they have fulfilled and half-filled electronic configuration respectively and (b) has lowest ionization energy due to having unstable electronic configuration.

Ans: Though sodium andMg⁺ion have same number of electrons the atomic size of Mg⁺is smaller than Na. Since, smaller the size, the greater is the nuclear force of attraction for valance electrons due to which removal of electron from Mg⁺requires more energy than sodium.

Ans: Electronegativity and electron affinity differs from each other in the following ways:

According to increasing electronegativity: M^-...