CBSE Questions for Class 11 Medical Chemistry Classification Of Elements And Periodicity In Properties Quiz 3 - MCQExams.com

A diagonal relationship exists between certain pairs of diagonally adjacent elements in the second and third periods. These are the first 20 elements in the periodic table. 

For example, pairs lithium (Li) and magnesium (Mg), beryllium (Be) and aluminium (Al), boron (B) and silicon (Si) exhibit similar properties. Boron and Silicon are both semiconductors. 

Thus, Magnesium and Lithium have similar properties.

Hence, the correct answer is option $$\text{A}$$.

• Sodium $$Na$$ and Potassium $$K$$ are present in the group $$I$$ that is alkali metal elements. While Magnesium $$Mg$$ and Calcium $$Ca$$ are group $$II$$ alkaline earth metals.
• As we move from left to right in the periodic table the ionization energy increases as new electrons enter the same shell so, effective nuclear charge increases.
• So, $$Na$$ and $$K$$ are more reactive than $$Mg$$ and $$Ca$$ respectively.
• And as we go down the group number of shells increases so atomic size increases so, ionization energy decreases.
• As ionization energy decreases the reactivity of metal increases.
• So, Potassium is the most reactive metal.
• This can be illustrated by using metal reactivity series as shown below:
                       
• 
  
  $$\bf{Final \ Answer}:$$ Option $$C$$

Second option is wrong as $$N$$ have greater first ionization enthalpy than $$O$$ due to the stable half filled p orbital of $$N$$.

$$\therefore$$ Order is $$B<C<O<N$$

$$\rightarrow Al^{3+}<Mg^{2+}<Na^{+}<F^{-}$$ (positive charge increases, size decreases)

$$\rightarrow Li<Na<I<K<Rb$$ (Down the group, size increases)

$$\rightarrow I<Br<F<Cl$$ (Down the group, electron gain enthalpy increases by $$\triangle H_{Cl}^{EGE} > \triangle H_F^{EGE} $$ due to small size of Fluorine.

Hint: Electrons are filled in the orbitals in order of increasing energies.

Explanation: 

The oxides obtained on the decomposition of ferrous sulfate are $$S{O_2}$$ and $$S{O_3}$$ the reaction is shown as;

$$ 2FeSO_4 \rightarrow Fe_2O_3 + SO_2 + SO_3 $$

So the oxides are of $$S$$ and it is also a yellow solid having properties of catenation and allotropy.

The atomic number of sulfur is $$16$$ the electronic configuration is $$K,L,M::2,8,6$$. 

Hence, the correct answer is $$D$$

Correct Option: $$D$$

The metallic character is used to define the chemical property that metallic elements present. Generally, metals tend to lose electrons to form cations. Nonmetals tend to gain electrons to form anions. They also have a high oxidation potential therefore they are easily oxidized and are strong reducng agents. Thus the property which regularly increases down the group in the periodic table is Reducing nature.