D block

Part 1 of the series (d- and f- block)! Question mode: Flashcards only. Answer mode: Answer with Definition. Suitable for JEE Mains aspirants and probably also JEE Advanced. Catered towards IAT aspirants.

What is the general electronic configuration of d-block elements?

(n-1)d^{1-10}\ ns^{1-2}

What are the elements of d-block in the fourth period?

scandium

titanium

vanadium

chromium

manganese

iron

cobalt

nickel

copper

zinc

What are the elements of d-block in the fifth period?

yttrium

zirconium

niobium

molybdenum

technicium

ruthenium

rhodium

palladium

silver

cadmium

Which elements from first transition series have irregular electronic configuration?

Chromium, Copper

Out of the total 40 elements in the d-block, how many are non-transitional? Which ones are those?

4 are non-transitional.

1. Zinc

2. Cadmium

3. Mercury

4. Copernicium

Why are Zinc, Cadmium, Mercury, and Copernicium non-transitional?

Because their (n-1)d subshells are complete. Transitional means that (n-1)d subshells are incomplete.

What are the elements from the second transition series that have irregular electronic configuration?

1. niobium

2. molybdenum

3. ruthenium

4. rhodium

5. palladium

6. silver

What are the elements from the third transition series that have irregular electronic configuration?

platinum and gold

Which element in the d-block has the highest melting point?

Tungsten

Which element in the d-block has the highest density?

rhenium

What is the range of atomic numbers in the first transition series?

21-30

What is the range of atomic numbers in the second transition series?

39-48

What is the range of atomic numbers in the third transition series?

57, 72-80

What is the smallest (by atomic size) element in the d-block?

nickel

Across a period, why does atomic size / atomic radius first decrease then increase again?

As the electrons are added to the penultimate shell across the period, the shielding effect increases and eventually outweighs the nuclear charge effect and thus pushes electrons away further

What is the nuclear charge effect?

It is the force of attraction experienced by valence electrons due to the positive charge in the nucleus

What is the shielding effect?

It is the repulsion of valence electrons due to inner subshell electrons

Which subshell provides the most shielding?

s subshell

Which subshell provides the least shielding?

f subshell

What is lanthanide contraction?

It is the decrease in size of atoms due to the f subshell

What is transition contraction?

It is the decrease in size of atoms due to the d subshell

What is the trend of atomic size across the period in the d block?

Atomic size first decreases then increases.

What is the trend of atomic size down the group in the d block?

Generally atomic size increases downward.

Why are the atomic sizes of the second and third transition series similar?

Because of lanthanide contraction (poor shielding by f subshell)

Which group is not affected by lanthanide contraction in the d block?

the first d-block group (group 3)

D block elements can donate electrons from which subshells?

ns and (n-1)d subshells

Why do zinc, mercury, and cadmium have the same metallic properties as the other elements in d block?

Because their ns and (n-1)d subshells are complete

What are the two types of bonding in d-block elements?

1. covalent bonding

2. metallic bonding

Which subshell participates in covalent bonding in d-block elements?

unpaired electrons (n-1)d subshell

Which subshell participates in metallic bonding in d-block elements?

ns subshells.

Metallic bond is due to electrostatic attraction between which two things?

free electrons and positive kernels

How do melting point and boiling point depend on metallic bond strength and number of unpaired electrons?

they are directly proportional

What is the trend of melting point across a period in d-block?

first it increases, and then it decreases

Why does the melting point of elements first increase across a period then decrease?

Because it increases with the increase in unpaired electrons and decreases with the decrease in unpaired electrons.

Which element has the lowest melting point in the d block besides zinc, mercury, and cadmium?

copper. then manganese

In the first transition series, what is the element which has the highest melting point?

Chromium

which block has a higher melting point on average; s block or d block? why?

d-block because more unpaired electrons

What is the trend of melting and boiling point down a group in the d-block?

melting and boiling point increases down the group

How does enthalpy of atomization vary with metallic bond strength, or number of unpaired electrons?

they are directly proportional

What is the trend of enthalpy of atomisation across a period in d-block?

first it increases then it decreases

Why does the enthalpy of atomization across a period in d-block first increase then decrease?

Because it depends on the number of unpaired electrons, which first increase and then decrease

What is the trend of solid density across a period in d-block?

First it increases then it decreases

Why does solid density first increase then decrease along a period in d-block?

Because it is inversely proportional to atomic size.

What is the trend of solid density down a group in d-block?

It increases. third transition series has a much higher density than the second and so on.

Why is the ionisation enthalpy of Cu^+ so high?

Because half-filled or fully-filled subshells are more stable than otherwise.

the configuration of Cu^+ is [Ar]3d^{10}.

Why is the ionisation enthalpy of Cr^+ so high?

Because half-filled or fully-filled subshells are more stable than otherwise.

the configuration of Cr^+ is [Ar]3d^{5}.

What is the trend of first ionisation enthalpy across a period in d-block?

increases across a period

What is the trend of first ionisation enthalpies down a group in d-block?

increases down a group

3d\approx 4d < 5d (except for group three)

What are the possible oxidation states of scandium? Which are the most common?

+3

none more stable

What ae the possible oxidation states of Titanium? Which are the most common?

+2, +3, +4

+4 is the most common

What are the possible oxidation states of Vanadium? Which are the most common?

+2,+3,+4,+5

+5 is the most common

What are the possible oxidation states of Chromium? Which are the most common?

+1,+2,+3,+4,+5,+6

+3 and +6 are most common

What are the possible oxidation states of Manganese? Which are the most common?

+2,+3,+4,+5,+6,+7

+2 and +7 are the most common

What are the possible oxidation states of Ferrum? Which are the most common?

+2,+3,+4,+5,+6

+2 and +3 are the most common

What are the possible oxidation states of Cobalt? Which are the most common?

+2,+3,+4

+2 and +3 are the most common

What are the possible oxidation states of Nickel? Which are the most common?

+2,+3,+4

+2 is the most common

What are the possible oxidation states of Cuprum? Which are the most common?

+1,+2

+2 is the most common

What are the possible oxidation states of Zinc? Which are the most common?

+2 is the only one, it is also the most common

What is the most common oxidation state in the d-block?

+2

What is the highest oxidation state in d-block? Which elements have this oxidation state?

+8

Osmium and Rhenium show this oxidation state

Which element shows the maximum number of oxidation states in d-block?

Manganese

Which ion of chromium is stable in aqueous solution?

Cr^{+3}

Why is Cr^{+3} stable in aqueous solution?

Due to the influence of the lone pairs from oxygen (in H_2O), the subshell splits into three and two orbitals, one group half-filled and one group empty, which is very stable.

Why is Cr^{+2} a good reducing agent in aqueous solution?

Because it gets oxidised to Cr^{+3}, which is very stable in aqueous medium.

Why is Cr^{+6} a good oxidising agent?

Because it gets reduced to Cr^{+3}, which is very stable in aqueous medium.

How does the stability of an oxidation state vary with covalent nature (attracting electrons to itself)?

It is directly proportional

How does the value of an oxidation state vary with ionic nature?

it is inversely proportional

How does the value of an oxidation state vary with acidic nature (attracting lone pairs to itself)?

It is directly proportional

How does the value of an oxidation state vary with basic nature?

it is inversely proportional

How does the value of an oxidation state vary with size of atom?

it is inversely proportional

An atom with a lower oxidation state is more _____

(ionic, covalent)

ionic

An atom with a higher oxidation state is more _____

(ionic, covalent)

covalent

An atom with a lower oxidation state acts as a(n) _______ agent

(reducing, oxidising)

reducing agent

An atom with a higher oxidation state acts as a(n) _______ agent

(reducing, oxidising)

oxidising agent

Do atoms with lower oxidation states form fluorides and oxides?

no

Do atoms with higher oxidation states form fluorides and oxides?

yes

What happens to Cu^+ in aqueous state?

It undergoes deproportionation

What is deproportionation of Cu^+?

In aqueous state, two Cu^+ ions become one Cu^{+2} and one Cu.

Why does Cu^+ undergo deproportionation in aqueous state?

Because Cu^+ is less stable than Cu and Cu^{+2}.

What is the trend of stability of higher oxidation states down the group?

It increases down the group.

Why do atoms with higher oxidation states from the second and third transition series not act as good oxidising agents?

Because their higher oxidation states are very stable, they don’t need to be reduced.

Why do atoms with higher oxidation states from the first transition series act as good oxidising agents?

Because their higher oxidation states are not stable at all, and carnally desire to be reduced.

Do atoms with lower oxidation states form bromides and iodides?

yes

Do atoms with higher oxidation states form fluorides and oxides?

no

Why do ions of transition metals show different colours?

Due to presence of unpaired electrons in (n-1)d subshell.

can ions with no unpaired electrons show colours?

no

What is the colour of V^{+2}?

violet

What is the colour of Mn^{+3}?

violet

What is the colour of V^{+3}?

green

What is the colour of Fe^{+2}?

green

What is the colour of Ni^{+2}?

green

What is the colour of V^{+4}?

blue

What is the colour of Cr^{+2}?

blue

What is the colour of Co^{+3}?

blue

What is the colour of Cu^{+2}?

blue

What is the colour of Mn^{+2}?

pink

What is the colour of Co^{+2}?

pink

What is the colour of Fe^{+3}?

yellow

What is the colour of Cr^{+3}?

ruby and emerald

What is the colour of Cr_2O_7^{-2}?

orange