The seven Basic SI units

Name of Unit	Physical quantity	Symbol
Meter	Length	m
Kilogram	mass	kg.
Second	time	s(sec.)
Ampere	Electric current	A
Kelvin	Temperature	K
Candela	Light intensity	cd
Mole	Amount of substance	mol.

Some common SI Derived Units

 

Physical quantity	Name of Unit	Symbol of Unit	Definition in SI Basic Units
Area	-	-	m2
Volume	-	-	m3
Density	-	-	Kg/m3 or Kg m-3
Speed	-	-	m/s or m s-1
Acceleration	-	-	m/s2 or ms-2
Force	Newton	N	Kg ms-2
Pressure	Pascal	Pa	Kg m-1S-2 or Nm-2
Energy	Joule	J	Kg m2 s-2
Power	Watt	W	Kg m2s-3 or Js-1
Frequency	Hertz	Hz	s-1
Electric charge	Coulomb	C	As
Electric potential difference	Volt	V	JA-1S-1 or Kg m2s-3 A

 

The seven crystal Systems

Crystal Systems	Axial distances	Angles	Examples
Cubic	a = b = c	a = b = g = 98°	Nacl, Kcl, Diamond
Tetragonal	a = b = c	a = b = g = 90°	Sno2, White tin
Arthortrombic	a = b = c	a = b = g = 90°	Rhombic sulphur, KNO3
Monoclinic	a = b = c	a = g = 90°; b = 90°	Monoclinic sulphur, Na2So4 10H2o
Hexagonal	a = b = c	a = b = 90°; g = 120°	Graphite, Mg
Rhombohedral	a = b = c	a = b = g = 90°	Calcite
Triclinic	a = b = c	a = b = g = 90°	CuSO4.5H2O,Potassium dichromate

The Different types of unit cell which concescist in different crystal systems

Crystal System                            Types of Lattices
1. Cubic                                     Simple, Face centred, Body centred
2. Tetragonal                              Simple, Body centred
3. Orthorhombic                           Simple, Face centred, Body centred
                                                and end centred
4. Monoclinic                               Simple, End centred
5. Rhombohedral                           Simple
6. Triclinic                                   Simple
7. Hexagonal                                Simple

Electronic configurations of Elements (First 20)

Act no.     Elements     orbital Electronic configuration

1.	Hydrogen	IS1
2.	Helium	IS2
3.	Lithium	IS2	2S1
4.	Beryllium	IS2	2S2 2Px1
5.	Boron	IS2	2S2 2Px1 2Py1
6.	Carbon	IS2	2S2 2Px1 2Py1
7.	Nitrogen	IS2	2S2 2Px1 2Py1 2Pz1
8.	Oxygen	IS2	2S2 2Px2 2Py1 2Pz1
9.	Fluorine	IS2	2S2 2Px2 2Py2 2Pz1
10.	Neon	IS2	2S2 2Px2 2Py2 2Pz2
11.	Sodium	IS2	2S2 2Px2 2Py2 2Pz2	3S1
12.	Magnesium	IS2	2S2 2Px2 2Py2 2Pz2	3S2
13.	Aluminum	IS2	2S2 2Px2 2Py2 2Pz2	3S2 3Px1
14.	Silicon	IS2	2S2 2Px2 2Py2 2Pz2	3S2 3Px1 3Py1
15.	Phosphorus	IS2	2S2 2Px2 2Py2 2Pz2	3S2 3Px1 3Py1 3Pz1
16.	Sulphur	IS2	2S2 2Px2 2Py2 2Pz2	3S2 3Px2 3Py1 3Pz1
17.	Chlorine	IS2	2S2 2Px2 2Py2 2Pz2	3S2 3Px2 3Py2 3Pz1
18.	Argon	IS2	2S2 2Px2 2Py2 2Pz2	3S2 3Px2 3Py2 3Pz2
19.	Potassium	IS2	2S2 2Px2 2Py2 2Pz2	3S2 3Px2 3Py2 3Pz2	4S1
20	Calcium	IS2	2S2 2Px2 2Py2 2Pz2	3S2 3Px2 3Py2 3Pz2	4S2

 

Number of elements in different Periods

Period	Principal valency shell (=n)	Orbitals being filled up	Electrons to be accommodated	Number of elements
First	n = 1	1S	2	2
Second	n = 2	2S, 2p	2 + 6	8
Third	n = 3	3S, 3p	2 + 6	8
Fourth	n = 4	4S, 3d, 4p	2 + 10 + 6	18
Fifth	n = 5	5S, 4d, 5p	2 + 10 + 6	18
Sixth	n = 6	6S, 4g, 5d, 6p	2 + 14 + 10 + 6	32
Seventh	n = 7	7S, 5g, 6d, 7p	2 + 14 + 10 + 6	32

Important terms, concepts and formule.

Normality (N) - It is defined as the number of gram equivalents of solute per liter of
solution.

                 No of gram equivalents of solute
Normality  = -------------------------------
                   Volume of solution in liters

              Conc. of solution in grams/liter        W_(g)
           =------------------------------ = -------
                     Gram equivalent mass          GEM x V_(L)

Molality - It is defined as males of solute per kilogram of solvent.

                Moles of solute
Molality = ----------------------
               Mass of solvent in Kilograms

                  Moles of solute (g)
            = ----------------------
               GMM x Mass of solvent (kg)

Mole fraction - It is defined as the ratio of the moles of solute to the total no. of moles of all the components in solution. If n_A and n_B are the numbers of moles of solute and solvent respectively, the male fraction, x_A of the solute is given as

             n_A
X_A = -------------
          n_A + n_B

Parts per million (ppm) - It is defined as the number of parts by mass of solute per million.
parts by mass of solution.
Mass % - It is the amount of solute present in 100g. of solution
      W_(Solute)
%=-------------- x 100
      W_(Solution)
Molarity and normalities can be directly calculated from % strength if density is known.

               % x 10 x d
Molarity =------------          
                  GMM

             % x 10 x d
Normality =------------
                  GEM

Matter - Anything that occupies space and has mass.
Element - A pure substance which can neither be decomposed into nor built from simpler substances by any physical or chemical method. It contains only one kind of atoms.

Compound - A pure substance which can be decomposed into simpler substances by some suitable chemical method. It contains only one kind of molecules.

Mixture - A substance obtained by simple mixing of two or more pure substance.

Law of consernation of Mass - During any physical or chemical change total mass of the products formed is equal to the total mass of the reactants consumed.

Law of constant composition - A chemical compound always contains same elements combined together in same proportion by mass.

Law of Multiple Proportions - When two elements combine with each other to form two or more than two compounds then the masses of one of the elements that combine with the fixed mass of the other, bear a simple whole number ratio to one another.

Law of Rriprocel Proportions - When two elements combine separately with a fixed mass of a third element, then the ratio of their masses in which they do so is either same or some whole numbers multiple of the ratio in which they combine with each other. This law is also known as law of equivalent proportions.

Gay Lussac's Law -- When gases react with each other they do so in volumes which bear a simple whole number ratio to one another and to the volumes of products, if there are also gases, provided all volumes are measured under similar conditions of temperature and pressure.

Avogadro's Law - Equal volumes of all gases under similar conditions contain equal number of molecules.

Atom - The smallest particle of an element that takes part in chemical reactions.

Molecule - The smallest particle of a substance that has independent existence.

Atomicity - The number of atoms in a molecule of the elementary substance.

Atomic Mass Unit - One - twelth of the actual mass of an atom of carbon (C-12). It is equal to 1.66 x 10^-27 Kg.

Atomic Mass - The average relative mass of an atom of the element as compared with mass of a carbon atom (C-12) taken as 12 a.m.u.

Molecular Mass - The average relative mass of a moleculeas the substance as compared with mass of an atom of carbon (C-12) takes as 12 a.m.u.

Gram Atomic Mass (Gram-atom) - Quantity of the element in grams that is numerically equal to its atomic mass.

Gram Molecular Mass (Gram-Molecule) - Quantity of the substance in grams that is numerically equal to its Molecular mass.

Avogadro's Number (No) - 6.023 X 10²³

Loschmidt Number - The number of molecules in 1cm³ of gas at N.T.P. Its numerical value as 2.687 x 10²²

Mole - 6.023 x 10²³ specified particles.

Molar mass - Mass of one mole particles of the substance.

Gram Molecular Volume (G.M.V.) - Volume occupied by one mole molecules of the gaseous substance. Its value is equal to 22.4 L and N.T.P.
                                              Gram atomic mass           
 Mass of one atom in grams -    ---------------------
                                               6.023 x 10²³  

                                            Gram molecular mass
Mass of one molecule in grams - -------------------
                                              6.023 x 10²³

                           1
One a.m.u. = -------------- g
                   6.023 x 10²³

The reciprocal of Avogadro number is called AVOGRAM.

Empirical Formula - The formula which gives the simplest whole number ratio of atoms of different elements present in the molecule of the compound.

Molecular formula is whole number multiple of empirical formula.

Molarity (M) - Number of moles of solute per litre of solution. Expressed as moles per litre or moles per dm³

For Dilution - M₁ V₁ = M₂ V₂

- For mixing two solutions of the same substance, M₁ V₁ + M₂ V₂ = M₃ (V₁ + V₂)
- Molarity changes with change in temperature because volume of the solution changes with change in temperature.

              Mass of solute in grams per liter of solution
Molarity =------------------------------------------          
                  Gram molecular mass in solute

             Moles of solute
or =---------------------------
          volume in solution in liters 

Limiting Reagent - The reactant that is completely consumed during the reaction.

- Matter is found in three states, Solids, Liquids and Gases.
- In gaseous state, the particles move rapidly in all the directions and have large voids.
Gas laws - The generalisations regarding the behavior of gases.

Boyle's Law - The volume of a definite mass of a gas is inversely proportional to the pressure at constant temp.

Charle's Law - The volume of definite mass of a gas is directly proportional to the temperature. (in Kelvins) at constant pressure.

Dalton's Law - The pressure of the mixture of non-reacting gases is equal to the sum of these partial pressure when enclosed in the same volume under similar conditions.

Graham's Law of diffusion - The rate of diffusion of gases (v/t) is inversely proportional to square root their densities under similar conditions.

Absolute zero - The hypothetical temp. at which all the gases are supposed to occupy zero volume. Its numerical value on celcius scale is -273.15°C.

Vapour density of a gas - It is the ratio of the mass of certain volume of gas to the mass of same volume of hydrogen under similar conditions.

Molecular mass of gas = 2X vapour density.

Liquid state - In liquid state the particles are loosely packed with voids and molecular motion much smaller than those in gases.

Evaporation - The process of escape of liquid molecules from its surface into the gas phase is called evaporation. It depends upon nature of liquid temperature and surface are of liquid.

Vapour pressure - The pressure exerted by the vapours of the liquid in equilibrium with the liquid at particular temperature. Vapour pressure of a liquid depends upon temperature.

Boiling point of liquid - The temprature at which, the vapour pressure of the liquid becomes equal to the atmospheric pressure (or pressure on the surface of liquid) is called boiling point of the liquid.

Solid state - The state of matter in which the particles are packed closely with minimum voids.

Space Lattice - A regular three-dimensional arrangement of points in space.

Unit cell - A three dimensional group lattice points that generates the whole lattice by translation or stocking.

- In cubic system, there are three Units cells, normely, simple cubic, fare centred and Body centered.
- Of the three physical states of matter, the gaseous state is most random state and solid state is least random.

Boyle's Law equation (at constant T, n) Va 1/p or P₁ = P₂V₂

Charle's Law equation (at constant P,n) V a T or

V₁        V₂
--   =   ----
T₁        T₂

Avogadro's Law (at constant T, P) V a n

Ideal gas equation - PV = n R T or

P₁V₁     P₂V₂
-----=  ----
T₁        T₂

Graham's Law .r

Dalton's Law - P = P₁ + P₂ + P₃

Molecular Speeds -

K.E of gas a T . KE of N molecules = 3/2 RT

- A gas with higher vapour density is relatively more heavier.
- Average vapour density of dry air = 14.4

Van. Der Waal equation = (P + an²/V²) (V - nb) = nRT

Brag's equation n l = 2d sinq

Cathode Rays = consist of negatively charged material particles called electrons.

Electrons - Fundamental sub-atomic particles carrying negative charge (1.602 x 10^-19 coulombs) and having mass 9.1 x 10^-3 Kg. Discovered by J.J.Thomson.

- Charge to mass (e/m) ratio for electrons is 1.76 x 10⁸ c/g.

Anode Rays - Consist of positively charged ions. e/m ratio for the ions in the anode rays depends on the nature of the gas taken in the discharge tube. Discovered by Goldstein.

Proton - A subatomic positively charged particle, having charge 1.602 x 10^-19 C and having mass 1.67 x 10^-27 Kg. Mass of proton is nearly 1837 times the mass of an electron.

Alpha particles - He²⁺ ions or helium nuclei.

Rutherford's Experiment - led to the discovery of nucleus.
Radius of nucleus (~ 10^-15m) is very small as compared with radius of atom (~ 10^-10m).

Neutrons - Sub - atomic neutral particles having mass 1.675 x 10^-27Kg. Discovered by James Chadwick.

Atomic Number (Z) = Number of protons = Numbers of electrons.

Mass Number (A) = Number of protons + Number of neutrons.

Isobars - Atoms of different elements having same mass numbers.

Isotopes - Atoms of same element having different mass number.

Isotones - Atoms of different elements having same number of neutrons.

- s- orbitals are spherically symmetrical.
- p- orbitals are dumb-bell shaped.

Degenerate orbitals - The orbitals having equal energy.

Electronic Configuration - Distribution of electrons among various orbitals in an atom.

Aujbar rule - The orbital are filled in the order of increasing energy, starting with the orbital of lowest energy.

Paul's exclusion principle - No two electrons in an atom can have same set of all the four quantum numbers. It implies from this principle that only two electrons having opposite spins can be accommodated in an orbital.

Hewd's Rule of Maximum Spin Multiplicity - The pairing of electrons in orbitals of a particular sub-shell can't take place until all the orbitals of the sub-shell are singly occupied. These singly occupied orbitals should have electrons with parallel spin.

Periodic Table - Arrangement of elements in the increasing order of atomic number such that elements with similar properties fall under same vertical column.

Group - A vertical column of elements in the periodic table.

Period - A horizontal row of elements in the periodic table.

- Long form of Periodic Table has 18 groups and 7 periods. Sixth period is the longest and first period is the smallest.

- s-Block Elements - Elements of groups 1 and 2. Their general electronic configuration is ns^1-2

- p-Block Elements - Elements of group 13, 14, 15, 16, 17 and 18. Their general electronic configuration is ns²np^1-6

- d-Block Elements - Elements of groups 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12 also known as transition elements. Their general electronic configuration is (n-1)^d1-10 ns^1-2₄₆. Also Pd is exception (4d¹⁰ 5s⁰)

- j-Block Elements - The two horizontal rows of elements at the bottom of the table. Also known as inner transition elements. Their general electronic configuration is (n - 2) j^1-14 (n - 1)d^0-1ns².