Basic Concepts of Chemistry and the s-Block Elements

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CHAPTER TWO

Some Basic Concepts of Chemistry

INTRODUCTION

All developments in chemistry are based on scientific approach. A scientist is always very keen to perform experiments, make observations and draw inferences from the observations. In order to achieve correct results, he has to rely upon the various skills connected with the measurements.

Chemistry is the science of molecules and their transformations which deals with the study of matter, its composition, the changes that matter undergoes and the relation between changes in composition and changes in energy. Chemistry plays a central role in science and is often intertwined with other branches of science. Chemistry plays an important role in meeting human needs for food, health care products.

The term "Stoichiometry" refers to calculations based on chemical equations. A chemical equation is a symbolic representation of chemical reaction. It indicates the number of moles, molecules, mass and volume (in case of gases) of reactants and their respective products formed.

MATTER

Some Basic Concepts of Chemistry

CHAPTER THIRTEEN

INTRODUCTION

THE S-BLOCK ELEMENTS

The s-Block Elements

Cause of diagonal relationship

CHAPTER THIRTEEN

INTRODUCTION

THE S-BLOCK ELEMENTS

The s-Block Elements

Cause of diagonal relationship

Ionization Enthalpy

Hydration Enthalpy

Physical Properties

(i) Flame colouration

(ii) Photoelectric Effect

Chemical Properties

(i) Reactivity towards air

(ii) Reactivity towards water

(iii) Reactivity towards dihydrogen

The s-Block Elements

(v) Reducing nature

(vi) Solutions in liquid ammonia

Reducing Property

Reaction with sulphur and phosphorous : All metals form sulphides and phosphides

Reaction with mercury : Alkali metals combine with mercury to form amalgams. The reaction is highly exothermic in nature

(ii) Halides

(iii) Salts of oxo-acids

The s-Block Elements

EXAMPLE TWO : The main oxides formed on combustion of Li, Na and K in excess of air are, respectively

ANOMALOUS PROPERTIES OF LITHIUM

Points of difference between Lithium and other Alkali Metals

Medical une Juan Foundon

Points of similarities between Lithium and Magnesium

The major similarities are

EXERCISE

Compounds of Sodium

Properties:

EXAMPLE SIX: What is the best description of the change that occurs when sodium oxide is dissolved in water?

Two. Sodium Peroxide (Na two O two):

Three. Sodium Hydroxide (Caustic Soda) (NaOH):

Thus, NaOH is taken out from inner compartment and evaporated to give solid NaOH. Properties of Sodium Hydroxide :

Preparation:

Board and Competitive Exams

Five. Sodium Bicarbonate (Baking Soda) Na H C O three :

Properties:

Seven. Sodium Sulphate Na two S O four :

Potassium K

Compounds of Potassium

K O two. Preparation:

Potassium hydroxide is manufactured by electrolysis of KCI solution. Properties:

Three. Potassium Carbonate K two C O three : Preparation:

Board and Competitive Exams

EXAMPLE Eight:

EXERCISE

Twenty-seven. Which of the following is paramagnetic? One. KO two. Na two O two

Atomic and Physical Properties of the Alkaline Earth Metals

Electronic Configuration

Ionization Enthalpies

Hydration Enthalpies

Physical Properties

EXAMPLE Ten: Which one of the following alkaline earth metal sulphates has its hydration enthalpy greater

Chemical Properties

Chemical Properties of Group-two Elements

Board and Competitive Exams

Uses of alkaline earth metals

Comparison of group one and two metals

ANOMALOUS BEHAVIOUR OF BERYLLIUM

Preparation :

Three. Magnesium Carbonate (MgCO3):

Four. Magnesium Chloride (MgCl2):

Properties:

The s-Block Elements

Five. Magnesium Sulphate (MgSO4):

Calcium (Ca)

One. Calcium Oxide (CaO) : Preparation :

Preparation :

The s-Block Elements

Board and Competitive Exams

EXAMPLE twelve : Predict the outcome of the following reactions and write balanced equations.

EXAMPLE thirteen :

CEMENT

The s-Block Elements

Board and Competitive Exams

Quick Recap Vedican

Overview

The text provides an overview of basic chemistry concepts, focusing on the nature of matter and the properties of s-block elements. It highlights the importance of these elements in both industrial applications and biological systems.

Key Points

1Chemistry is the science of molecules and their transformations
2Stoichiometry involves calculations from chemical equations
3s-block elements are grouped based on their outermost electron configurations
4Alkali metals are known for their reactivity and characteristic flame colors
5Biological fluids contain essential alkali and alkaline earth metal ions for functioning.

Details

Category: Physical Sciences

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