S-block Elements

Question 1

Alkali Metals or Group-1 Metals

Answer 1

Lithium
Sodium
Potassium
Rubidium
Cesium

Question 2

General electronic configuration of alkali metals

Answer 2

[ns]1

Question 3

Atomic Radius Comparison of Alkali Metals

Answer 3

Li<Na<K<Rb<Cs<Fr
Difference in radius b/w element: Na-Li>Rb-K>Fr-Cs

Question 4

Ionisation Energy Comparison of Alkali Metals

Answer 4

Li>Na>K>Rb>Cs>Fr

Question 5

Ionic Radius Comparison of alkali metals

Answer 5

Li+<Na+<K+<Rb+<Cs+<Fr+

Question 6

Melting and Boiling Point Comparison of Alkali Metals

Answer 6

It depends upon metallic bond strength.
Li>Na>K>Rb>Cs>Fr

Question 7

Density Comparison of Alkali Metals

Answer 7

Li<Na<K<Rb<Cs<Fr

Question 8

Flame colouration of alkali metals

Answer 8

Li: Carmine Red
Na: Golden Yellow
K: Lilac
Rb: Violet
Cs: Blue

Question 9

How do alkali metals react with moist and dry air?

Answer 9

Lithium forms nitride and oxide
Other elements form oxide

Question 10

How do alkali metals react with oxygen?

Answer 10

Oxide: Lithium
Peroxide: Sodium
Superoxide: Potassium, Rubidium, Cesium
BUT K AND Rb CAN FORM ALL THREE IF THEY WANT TO

Question 11

What is KO2 used for?

Answer 11

It is used in submarines for absorbing CO2 and to produce O2

Question 12

Oxides of alkali metals reaction

Answer 12

Na(exc.) + air → Na2O

Question 13

Solvay Process

Answer 13

Production of sodium carbonate with the help of NH3, CO2, and NaCl
Potassium carbonate cannot be formed from this process.

Question 14

Lablanc’s Method

Answer 14

K2CO3 can be prepared from this process using NaCl, H2SO4, and C as a reducing agent

Question 15

Heating effects on carbonates

Answer 15

All carbonates except for Na, K, Rb, Cs decomposes on heating giving CO2

Question 16

Alkaline Earth Metals

Answer 16

Beryllium, Magnesium, Calcium, Strontium, Barium, Radium

Question 17

Atomic Radius Comparison of Alkaline Earth Metals

Answer 17

Be<Mg<Ca<Sr<Ba<Ra

Question 18

Ionic Radius Comparison of Alkaline Earth Metals

Answer 18

Be+2<Mg+2<Ca+2<Sr+2<Ba+2<Ra+2

Question 19

Ionisation Energy of Alkaline Earth Metals

Answer 19

Be>Ca>Sr>Ba>Mg

Question 20

Melting Point of Alkaline Earth Metals

Answer 20

Be>Ca>Sr>Ba>Mg
The distance between the two layers is larger in the lattice of magnesium. Hence melting point of magnesium is the lowest.

Question 21

Density of alkaline earth metals

Answer 21

Ca<Mg<Be<Sr<Ba

Question 22

Flame colouration of alkaline earth metals

Answer 22

Ca: Brick Red
Sr: Crimson Red
Ba: Apple Green
Be and Mg do not show any colour

Question 23

Reaction of alkaline earth metals with air

Answer 23

M + air → MO + M3N2
Be + air → BURNING
Mg + air → FLASH

Question 24

Comparison of solubility in water for alkaline earth metals

Answer 24

Be>Mg>Ca>Sr>Ba

Question 25

Formation of lime water

Answer 25

CaO(quick lime) + H2O → Ca(OH)2(slaked lime) + H2O→ Ca(OH)2(s)(milk of lime) + H2O → Ca(OH)2 (lime water)(l)

Question 26

Uses of Lithium

Answer 26

Preparing parts of the aircraft, armour, electrochemical cells

Question 27

Uses of Sodium

Answer 27

Making sodium alloys and collant in fast nuclear reaction

Question 28

Uses of potassium

Answer 28

For fertiliser, soaps, and excellent absorber of CO2 in submarine

Question 29

Uses in beryllium

Answer 29

For the formation of alloys, and used in making windows of X-ray tables

Question 30

Uses of magnesium

Answer 30

Used in making alloys, milk of magnesia and toothpaste

Question 31

Uses of calcium

Answer 31

Extraction of metals from oxide which are difficult to reduce by carbon

Question 32

Uses of CaO

Answer 32

Manufacturing of cement Used in the purification of sugar

Question 33

Uses of Ca(OH)2

Answer 33

Manufacturing of mortar Whitewashing Manufacturing of glass and bleaching powder

Question 34

Uses of CaCO3

Answer 34

Used as marble Extraction of metals Antacid