ATOMS 4U

Generally we know that atomic size increases down the group from top to bottom due to increase in the number of valance shell . But then why the atomic size of gallium is less than aluminum ?  Because , in case of gallium due to presence of d-orbitals , size of gallium  decreases to greater extend . D orbitals have poor shielding effect . It means that they cannot shield the nuclear force on outer most electrons. Due to decrease in shielding effect and increase in nuclear force , size of Gallium becomes  smaller than Aluminum . But remember that , this case only for Gallium , remaining 4th period elements follow the same trend , that is atomic size increase down the group . Effects of decrease in size of Gallium  ●Increase in ionization enthalpy  Due to decrease in size of Gallium , it's Ionization enthalpy increases . Smaller the size , more will be nuclear force on valance electrons . Therefore more energy requires to remove electron from the outermost shell ....

Solubility of a molecule or substance in water depends on the formation of bonds  between then water and a molecule .  Ortho-nitrophenol (o-nitrophenol) molecule forms intramolecular bonds with itself . Intramolecular bond means bonding within the molecule .This leds to no free -OH bond available for Hydrogen bond formation . Due to this , there is less bonding between water and o-nitrophenol  On the other hands , para-nitrophenol(o-nitrophenol ) has a free -OH bond and can form strong intermolecular hydrogen bonding with water Molecules . Due to this they are more soluble in water . So , in short p-nitrophenol is more soluble than o-nitrophenol due to strong intermolecular hydrogen bonding

Electron gain enthalpy is the enthalpy Change take place when an electron is added to isolated gaseous atom . Electron gain enthalpy of halogens are highly negative because this process is exothermic in nature and large amount of heat is released . Fluorine is most electronegative element in the periodic table still it's  electron gain enthalpy is less than  Chlorine . Why Chlorine has High electron gain enthalpy than Flourine ? Size of fluorine is very small . So when an extra electron tries to attract toward this atom , their is large electron - electron repulsion take place between the outermost electrons and incoming electron . It becomes difficult for incoming electron to add up in the outermost shell . On the other hand , Chlorine is larger in size than flourine and when extra electron come in contact with this atom , Chlorine immediately tries to attract toward itself . Due to larger size , their is less electron - electron repulsion and it becomes easier fo...

Solid is a rigid and incompressible state of matter . Due to high intermolecular forces and less intermolecular distance ,they are very difficult to compress . They have a definite shape and definite volume . Solids are broadly classified into two types 1. Crystalline Solids 2. Amorphous Solids 1. Crystalline Solids   ●Solids in which the constituent particles are arranged in a definite and regular pattern is called as Crystalline Solids. ●They have long range order.  It means that the regularity in the arrangement of particles is up to long ranges ● They have sharp melting point . They do not melt at any temperature . When a particular temperature reached they start melting.  ● They are anisotropic in nature. It is a property of crystalline Solids to show different properties in different directions is called as anisotropy .  Crystalline Solids can be isomorphous or polymorphous . Isomorphous ●Two or more Substances having same Crystalline structures are...

Matter is anything that has a mass and occupy space . Ice  , pen , pencil ,dog , etc are examples of matter because they have some mass and they occupy space . There are basically three states of matter , ●Solid  ●Liquid ●Gas Solid   Solid is defined as rigid and incompressible state of matter .  Now the question is , why Solids are rigid and incompressible ? To answer this question , let's understand the properties of solids .  1.Solids have large intermolecular force of attraction . Intermolecular force is the force of attraction between to adjacent Molecules .  Higher the intermolecular force , more tightly they will attract each other and less movement of Molecules will occur . 2.Intermolecular distance in Solid is very less . Intermolecular distance is the distance between two adjacent molecules . Less the distance more will the intermolecular force of attraction . Intermolecular force is inversely proportional to intermolecular distance . ...

Boiling point is the temperature at which vapour pressure of liquid is equals to atmospheric pressure. Boiling point of any liquid depends on the length of carbon-carbon chain(parent chain) ,  functional group and branching in the parent chain.  Length of parent chain Boiling point increases with increase in the length of carbon-carbon  chain .This is because when length of chain increases , it increase the surface area of the chain. More the surface area , more will be the van der Waal's force of attraction and more energy requires to break this bond .  Boiling point of the member of same family and having same functional group increases with the length of chain . For example , boiling point of  Propane is more than ethane and boiling point of ethane is more than Methane. i.e Propane > Ethane > Methane . Branching in a  parent chain . Boiling point decreases with branching . This is because branching in the parent chain decreases the surf...

Chemistry is also known as the  "Central Science " because of it's applications in various fields like Medicine , biology , physics , engineering , etc. Modern chemistry plays an important roles in the field of medicine and pharmacy. Due to modern chemistry it became easier to resolve health related issues. Let's see some most commonly used medicine in daily life of human beings. 1. Antiseptics Antiseptics are the chemical substances use to  stop the growth of microorganisms on the wounds or cuts . They are either bacteriostatic(stop the growth of bacteria) or bactericidal(kills bacteria)  .  Chemicals like Boric Acid , Hydrogen Peroxide(about 3% concentration) and Iodine compounds are mostly used as antiseptic .  2. Disinfectants Disinfectants are the chemical substances used to kill microorganisms or stop their growth on non-living objects like table , chair . Phenol at high concentration of about 1-2 % is used as disinfectant  and at low conc...

Polar and non-polar Molecule  Polar Molecules are the Molecules whose net dipole moment is non-zero and non-polar Molecules are the Molecules whose net dipole moment is zero. What is dipole moment ? It is the product of charge on ions and distance between oppositely charged ions. Higher the charge on atoms or ions more will be the dipole moment .  Covalent bond is further classified as polar Covalent bond and non-polar Covalent bond . ●Polar Covalent bond  This type of bond is formed when there is electronegative difference between Covalently bonded atoms in a molecules .  More electronegative atom tries to attract shared electron toward itself . This leads to partial negative charge on more electronegative atom and partial positive charge on more electropositive atom . ●Non-polar Covalent bond  This type of bond is formed when the electronegative difference of atoms in a molecule is same or almost same .  Bonding electrons are equally shared be...

 In this post I have show top 10 most searched terms of Chemistry . Let's see what there are. 1. Ionization enthalpy  It is the amount of energy requires to remove an electron from the outermost shell of an isolated gaseous atom or ion.   During this process , atom absorb energy and therefore ionization enthalpy is endothermic in nature (absorption of energy takes place). Ionization enthalpy depends on the following factors  ◆Size of an atom or ion ◆nuclear force of attraction ◆Extra stability of half filled or completely filled orbitals In smaller size atoms , it is difficult to remove electron because the outermost electrons are tightly bounded to the nucleus(strong nuclear force ) . Therefore , it becomes difficult to remove electrons from smaller atoms but at the same time it become easier to remove electron from large sized atoms because the nucleus force acting on those outermost electrons are less and they are loosely bounded or attracted to t...

In this post I have shown some most important Chemical compounds and their Chemical Formulas along with their names Following are some Chemical compounds with respect to their names and Formulas Aqua Fortis ◆Nitric Acid(HNO3)  Baking Soda ◆Sodium Bicarbonate(NaHCO3) Brine/Rock Salt ◆Sodium Chloride(NaCl) Bleaching Powder ◆Calcium Hypochlorite(CaOCl2) LimeStone ◆Calcium Carbonate(CaCO3) Caustic Soda ◆Sodium Hydroxide(NaOH) Laughing Gas ◆Dinitrogen Oxide(N2O) Lime ◆Calcium Oxide(CaO) Oil of Vitriol ◆Sulphuric Acid(H2SO4) Plaster Of Paris ◆Calcium Sulphate Hydrate(CaSO4 .?H2O) Dry Ice ◆Solid CO2 Vinegar ◆Acetic Acid Solution(5% CH3COOH) Washing Soda ◆Sodium Carbonate Hydrate(Na2CO3. 10H2O) King Of Chemicals ◆Sulphuric Acid(H2SO4) Sand is made up of ◆Silicon Dioxide(SiO2) Slaked Lime is  ◆Calcium Hydroxide Chalk/Marble Contains ◆Calcium Carbonate(CaCO3) Marsh Gas ◆Methane(CH4) Potash ◆Potasium Carbonate(K2CO3) So , these are some most important Chemical compounds with ...

Comparison of atom Comparing atom to the real world things will amaze you and  make you more curious towards the Chemistry subject. Let's start with some basic and then move on to the comparison part so that you can easily understand the comparison between Atom with human as well as other things. Basics of Atom   Atom is a basic unit of matter . Atom is made up of three subatomic particles  protons , Neutrons and electrons.  Central core part of  an Atom is called as Nucleus . Nucleus of an atom is made up of protons and neutrons except Hydrogen atom(H1) containing only 1 proton and no Neutron .  Electron revolve around the nucleus in particular orbit . Comparing Atom with Nucleus The size of an atom is about 10^-10 meters and the size of nucleus is about 10^-15 meters . After taking ratio of this two numbers , I  found that atom is  100000  times larger than the nucleus .  Comparing Atom with Earth A simple (not e...

Chemistry is also called as " Central Science " because we require the knowledge of Chemistry in various fields like physics , Biology , Biotechnology , Engineering and many more . Here are some basic terms to  boost your Chemistry concepts . Matter   Matter is anything having mass and occupy space . Examples : water , pen , cat , etc . States of matter Solid , liquid and gases are the basic states of matter .  Solid state Solids have fix shape and volume  Examples : Ice , Duster , Board , etc Liquid state Liquids have definite volume but no definite shape . Examples : water , petrol , Diesel , etc . Gases state Gases have no definite shape and volume . Examples : Air ,  Hydrogen gas , Helium gas , etc . They occupy entire space of the container .  Atom   Atom is the basic unit of matter . All matter is made up of atoms .  Subatomic particles of atom Atom is made up of subatomic particles, protons , Neutrons and electrons . Parts of at...

Which is the most acidic compound or Substance ? This question is difficult to answer because for this we have to find the acidic strength of all the compounds which are found or exist in nature..But don't worry , we have answer for this question.. First understand which compound is called as  acid Acid are those compound which can easily donate their H+ ion , easily accept an electron pair and show high resonance stabilization .  All this points have to consider while determine the acidic strength of a compound. After considering all this factors , it has been found that the most acidic compound is  Fluoroantimonic Acid . It's also considered as a Super Acid .  Super Acids are acids with acidic strength or acidity greater than 100% pure sulphuric acid Fluoroantimonic Acid is an inorganic  compound having Chemical formula H2SbF7.It is  prepared by reacting Hydrogen Fluoride(HF)and antimony pentachloride(SbF5) in 2 : 1 ratio . It is 10 quadrillion times m...

Acid can be found in your household Substances. In this post I have show some acidic household Substance with their acidic strength . Before going to the list of acidic Substances, We must know what actually acid is !! Acids are the Substance which can easily donate their H+ ions . This statement is only valid for Substance containing Hydrogen(H) then what about other Substance which doesn't contains H+ ions and still acidic.. So here is another statement : " Acid are the Substance which can easily Accept electron pair . They are generally electron deficient species. Now , Check out some Important Acidic household Substances with their Acidic values . ◆ Shampoo  ◆ Lemon / Orange ◆Milk or other dairy products ◆Coca-Cola / Soft drink ◆ Vinegar ◆Phenol Acidic nature of a Substance can be determined by using pH scale . For a Substance If the pH value is less than 7 then it will be acid , if more than 7 then it will be basic and if exactly 7 then it will be neutral in nature . Let...

Alkali metal(Group 1 ) and halogens(Group 17) are highly reactive because of some factors which I am going to discuss here. Alkali Metals(Group 1) First let me clear that Group 1 Element is also called alkali Metal because when they react with water they form strong alkaline(Strong Base with water) . Elements like Lithium , Sodium , Potassium , Rubidium , Caesium form strong bases with water  Halogens(Group 17) Group 17 elements are called halogen because the word " Halogen" came from Greek word which means " to make salt " . Element like Fluorine , Chlorine , Bromine and Iodine form salts when reacts with metals . High reactivity of Alkali Metals(Group 1) Coming to point , Group 1 elements are highly reactive because of their large atomic Size and low ionization enthalpy . Atomic Size and ionization enthalpy are inversely proportional to each other .  Ionization enthalpy is simply amount of energy requires to remove any electron from the outermost shell (atom must ...