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Chemistry Definitions : Basics of Atoms and Moles

Chemistry Page on Basics of Atoms and Moles

Atoms and Moles

Section 1 

Substances are Made of Atoms

I. Atomic Theory

-As early as 400 B.C., an atomic theory existed that stated that atoms are the building blocks of all matter
-Democritus was the first scientist who believed in atoms (Greek)
-It wasn't until the 1800s that atomic theory was revised based on scientific observations

 A. Law of Definite Proportion

 -Two samples of a given compound are made of the same elements in exactly the same proportions by mass regardless of the sizes or sources of the samples.
-Every molecule of the same type is made of the same number and types of atoms
-Example: Table Salt (Sodium Chloride)
 -consists of two elements in the following proportions by mass:
 -60.66% Chlorine
-39.34% Sodium
 -Every sample of table salt has these same proportions

 B. Law of Conservation of Mass

 -The mass of the reactants in a reaction equals the mass of the products
-Mass cannot be created or destroyed in ordinary chemical and physical changes

 C. Law of Multiple Proportions

 -If tow or more different compounds are composed of the same two elements, the ratio of the masses of the second element (which combines with a given mass at the first element) is always a ratio of small whole numbers.

 II. Dalton's Atomic Theory

 - Dalton revised the early Greek idea atomic theory in the 1800s into a scientific theory that could be tested by experiments
-Has five important principals
-Believed that elements are composed of only one kind of matter and compounds are made of two or more kinds
-Part of his theory that was incorrect is the fact that like atoms can combine with like atoms (such as O2)
-Did not include the fact that atoms are made up of even smaller particles

Dalton's Theory Contains Five Principles

1. All matter is composed of extremely small particles called atoms, which cannot be subdivide, created, or destroyed
2. Atoms of a given element are identical in their physical and chemical properties
3. Atoms of different elements differ in their physical and chemical properties
4. Atoms of different elements combine in simple, whole-number ratios to form compounds
5. In chemical reactions, atoms are combined, separated, or rearranged but never created, destroyed, or changed
 Section 2: 

Structure of Atoms

 I. Subatomic Particles

 A. Electrons- negative charge
B. Nucleus- an atom's central region, which is made up of protons and neutrons
 1. Protons- positive charge. Number of protons is atomic number.
2. Neutrons- no charge.

 II. Atomic Number and Atomic Mass

Elements differ from each other in the number of protons their atoms contain
 -Atomic Number- the number of protons in the nucleus of an atom; the atomic number is the same for all atoms of an element
-Atomic numbers are always whole numbers
-Atomic number also reveals the number of electrons in an atom of an element because for an atom to be neutral, electrons must equal protons
 Mass Number is the Number of Particles in the Nucleus
 -Mass number- the sum of the numbers of protons and neutrons of the nucleus of an atom
Example:
mass number- atomic number= number of neutrons
In this example, the neon atom has 10 neutrons
number of protons and neutrons (mass number)= 20
 - number of protons (atomic number)= 10
 number of neutrons= 10
 -Mass as a number can vary among atoms of a single element
- All atoms of an element have the same number of protons but can have different numbers of neutrons
 Example 2: Determining the Number of Particles in an Atom
How many protons, electrons, and neutrons are present in an atom of copper whose atomic number is 29 and whose mass number is 64?
1. Gather info
 -The atomic number of copper is 29
- The mass number of copper is 64
protons= 29                                        64
electrons= 29                                   -29
                                                             35 neutrons
 - Different elements can have the same mass number
- Knowing just the mass number does not help identify the element
Ex: Some copper atom nuclei have 36 neutrons (therefore mass number = 65) Zinc atoms have 30 protons and 35 neutrons
- Isotopes of an Element Have the Same Atomic Number
- Isotope- an atom that has the same number of protons (atomic number) as other atoms of the same element has a different number of neutrons (atomic mass)
- There are two standard methods of identifying isotopes
- Write the mass number with a hyphen after the name of an element (called hyphen notation; ex. Bromine- 80)
- Shows the composition of a  nucleus as the isotope's nuclear symbol
- Nucleic Notation
         Ex. 126C        C= element symbol
                              12= mass number
                                6= atomic number

Chapter 3 Section 3:

Electron Configuration

I. Atomic Models

 -After the atomic theory was widely accepted by scientists, models of atoms were constructed.
-Building a model helps scientists imagine what may be happening at the microscopic level
-Models have limitations
-Models are modified or discarded as new information is found

 A. Rutherford's Model Proposed Electron Orbits

  •  From section 2 J.J. Thomson proposed that the electrons of an atom were embedded in a positively charged ball of matter
  • Named the plum-pudding model because it resembled English plum pudding, a dessert consisting of a ball of cake with pieces of fruit in it
  • In 190, Rutherford performed experiments that disproved Thomson's model.
  • Rutherford envisioned the electrons outside the nucleus orbiting like planets orbiting the sun
  • Because opposite charges attract, the negatively charged electrons should be pulled into the positively charged nucleus

B. Bohr's Model Confines Electrons to Energy Level

  •  Rutherford model was replaced two years later by a model developed by Niels Bohr, a Danish physicist
  • According to the Bohr model, electrons can be only certain distances from the nucleus
  • Each distance from the nucleus quantity of energy that an electron can have
  • The distance in energy between two energy levels is known as a quantum of energy

C. Electrons Act Like Both Particles and Waves

  •  Thomson's experiments demonstarted that electrons act like particles that have mass

II. Electrons and Light

  •  By 1900, scientists knew that light could be thought of as moving waves that have given frequencies, speed, and wavelengths
  • Wavelength- the distance between two consecutive peaks or troughs of a wave
    • units- meters
    • wavelength of light- 105 to less than 10-10 m  
  • Electromagnetic Spectrum- all the frequencies or wavelengths of electromagnetic radiation
  • Einstein proposed that light has the properties of both waves and particles
  • Light can be described as a stream of particle, the energy of which is determined by the light's frequency

A. Light is an Electromagnetic Wave

  •  When passed through a glass prism, sunlight produces the visible spectrum--all the colors of light that a human can see

B. Light Emission

  •  When a high-voltage current is passed through a tube of hydrogen gas, lavender-colored light is seen
  • When this light is only made up of a few colors called LINE-EMISSION SPECTRUM
  • Each element has a line-emission spectrum that is made of a different pattern of colors

C. Light Provides Info About Electrons

  •  Ground state- lowest energy state of a quantized system
  • Excited state- state in which an atom has more energy than it does as its ground state
  • If an electron gains energy, it moves from ground state to excited state
Chapter 3: Section 3

III. Quantum Numbers

  •  Quantum model- present-day model of the atom in which electrons are located in orbitals
- Electrons within an energy level are located in orbitals (regions of high probability for findings particular electron)
  • To define the region in which electrons can be found, scientists have assigned four QUANTUM NUMBERS
  • Quantum Number- a number that specifies the properties of electrons
-principal quantum number (n)
-angular momentum quantum number (l)
-magnetic quantum number (m)
-spin quantum number (+  ½ or -  ½) ( ↑ or ↓)
  •  Principal Quantum Number (n) - indicates the main energy level occupied by the electron
-values are positive integers such as 1, 2, 3,and 4
-As n increases, the electron's distance from the nucleus and the electron's energy increases
  •  Angular Momentum Quantum Number (l)- indicates the shape or type of orbital that corresponds to a particular sublevel.
  • Chemists use a letter code for this Number
l=  0 corresponds to an s orbital
l= 1 to a p orbital
l= 2 to a d orbital
l= 3 to an f orbital 
  •  Magnetic Quantum Number (m)- indicates the numbers and orientations of the orbitals around the nucleus
  • The  value of m takes whole-number values, depending on the value of l
  • The number of orbitals includes on s orbital, 3 p orbitals, 5 d orbitals, and seven f orbitals
  • Spin Quantum Number (symbolized by +  ½ or -  ½ and by  ↑ or ↓) - indicates the orientation of an electron's magnetic field
  • A single orbital can hold a maximum of 2 electrons, which must have opposite spins

A. An Electron Occupies the Lowest Energy Level Available

  •  Pauli Exclusion Principle helps you to write an electron configuration for an atom
  • Aufbau Principle- electrons fill orbitals that have the lowest energy first

B. An Electron Configuration is a Shorthand Notation

  •  The arrangement of the electrons can be shown by the nucleus's electron configuration
  • Sulfur has sixteen electrons:
1s2 2s22p6 3s2 3p4


 Section 4: Counting Atoms

I. Atomic Mass 

 - Atoms are so mall that the gram is not a very convenient unit for expressing their masses
-  Atomic Mass- the mass of an atom expressed in atomic mass units (amu)

II.Introduction to the Mole

- Mole- number of atoms in exactly 12 grams of carbon-12. It is the SI unit for the amount of a substance (
- Molar Mass- the mass in grams of one mole of a substance (g/mol)
- Avogadro's number- 6.022  x1023 The number of atoms or molecules in 1 mol.
 3.50 mol Cu x 63.55 x  g Cu                             
                            1 mol Cu

3.50  mol Cu x 63.55 x 1023 g Cu = 222 g Cu
                           1 mol Cu

II. Intro to the Mole

A. Chemists and Physicists agree on a Standard
  •  In 1960, a standard was set based on an isotope of carbon
  • Defines atomic mass unit (amu) as one twelfth of the mass of one carbon-12 atom
  • One amu= 1.6005402 x  10-27 kg

Activity series of metals in aqueous solutions

Chemistry - INORGANIC CHEMISTRY
Activity series of metals in aqueous solutions
@ www.chemistrynotesinfo.blogspot.com

What is Organic Chemistry

 ORGANIC CHEMISTRY

Organic chemistry is a branch of chemistry which involve the scientific study of structure, properties & reactions of organic species, compounds or organic materials, means matter have various forms found that contains carbon atoms. Study of structure of organic chemistry compounds includes use of spectroscopy techniques like IR Spectroscopy, Microwave Spectroscopy, NMR Spectroscopy, Mass Spectroscopy, X – Ray Diffraction, Electron Diffraction, Neutron Diffraction and other physical and/or chemical type of methods to examine chemical composition and chemical constitution of the organic chemistry compounds and materials to be analysed. This is article on what is organic chemistry at “chemistry notes info blog”. Study of properties of organic compound includes study of both physical properties as well as chemical properties of organic chemistry compounds, which uses the similar methods and also methods to evaluate the chemical reactivity to understand behaviour of organic matter (organic sample) in its pure form (if when possible), otherwise in solution, mixture forms. Study of chemistry of organic reactions includes the searching their possibility through use in the preparations of goal molecule or compounds like natural products, medicinal drugs, polymers, solvents, etc.) by their chemical synthesis, also focused on the study of  reactivity’s of the individual organic molecules. This article is about basics understanding of organic chemistry under post organic chemistry lecture notes at www.ChemistryNotesInfo.blogspot.com . Below is a 3D diagram of methane CH4 molecule in tetrahedral geometry with bond angle of 109 degree.
Structure of Methane - Organic chemistry lecture notes
Structure of Methane
Please leave your valuable comments below.


Pure Chemical substances

Pure Substances- a sample of matter, either a single element or a single compound that has definite chemical and physical properties
Element- a substance that cannot be separated or broken down into simpler substances by chemical means; all atoms of an element have the same atomic number

Types of pure substances:

  1.  
    1.  
      • Elements

      • Compounds

  1. Elements- 

                     elements are pure substances that contain only one kind of atom
    1. Has its own unique set of physical and chemical properties
    2. Has its own chemical symbol
    3. Molecule- the smallest of a unit of substance that keeps all of the physical and chemical properties that of the substance; it can consist of one atom or two or more atoms bonded together
    4. Diatomic elements- two of the same atom bonded together chemically
  1. Pure Substances

-Some elements have more than one form
-Allotrope- one of a number of different molecular forms of an element
-Compounds are Pure Substances
Compound- a substance made up of atoms of two or more different elements joined by chemical bonds

All about Matter ?

I. Density
Matter has Mass & Volume
  1. Matter- Anything that has mass and takes up space
  2. The space an object occupies is its volume
    1. Volume—a measure of the size of a body or region in three-dimensional space
    2. The method used to determine volume depends on the nature of the matter being examined
  3. Quantity of Matter is Mass

    1. Mass- a measure of the amount of matter in an object. It is not affected by the gravitational force
    2. Balances measure mass usually in grams
    3. It is the same no matter where it is in the universe
  4. Mass is NOT Weight

    1. Weight- the force produced by gravity action on mass
    2. Its value can change with the location of the object in the universe
    3. Measured in Newtons

II. Units of Measurement

  1. Mass & volume are properties that can be described in terms of numbers
    1. Numbers alone aren’t enough because their meaning might be unclear
    2. Units of measurement are needed with the numbers
Quantity- something that has magnitude, size, or amount
Unit- a quantity adopted as a standard of measurement
  1. System Internationale d’Units
    1. Seven base units
    2. Base units can be modified by attaching prefixes
  2. Derived Units

    1. Many quantities you can measure need units other than the seven basic SI Units
    2. These units are derived by multiplying or dividing the base units
  1. Properties of Matter

Properties of substances may be classified as physical or chemical

Physical Properties

  1. Characteristic of a substance that doesn’t involve a chemical change, such as density, color, or hardness
  2. Chemical Properties

    1. A property of matter that describes a substance’s ability to participate in chemical reactions
    2. Examples: reactivity with oxygen, sensitivity to light, exposure to heat
  3. Density

    1. Density- the ratio of mass to volume of a substance. Often expressed in grams/cm3 for solids and liquids and g/L for gases
Density= mass/volume or D=m/v
  1. Classifying Matter

-From the last section:
-Matter-anything that has mass and takes up space
-All matter is composed of Atoms
-Atom- the smallest unit of an element that maintains the properties of that element
Because matter exists in so many different forms, having a way to classify it is important for study.
It helps you to predict what characteristics a sample will have based on what you know about others like it.

Working with the Properties & Changes of Matter

  1. Working with the Properties & Changes of Matter

    • Chemical- any substance that has defined composition
    • Everything you see is made up of chemicals
    • Even things you cannot see are made up of chemicals
    • Some exist naturally
    • Some are manufactured
    • Chemical Reaction- the process by which one or more substances change to produce one or more different substances

  1. Physical States of Matter

    • Type and arrangement of particles in a sample of matter determine the properties of the matter

    • Most matter is one of the three states of matter

A. Properties of the Physical State
Solids- fixed volume and shape
Rigid structure
Liquids- fixed volume and variable shape
Takes shape of container
Gases- neither fixed volume or shape
Particles move independently
Will fill any container they occupy
  1. Changes of Matter

Many changes of matter happen. Changes occur in two different ways:
  1.  
    • Physical Changes

    • Chemical Changes

A. Physical Change
Changes in which the identity of a substance doesn’t change
-Changes state
-Dissolving
-Crushing
B. Chemical Changes
Identifies of substances change and new substances form.
Mercury (II) oxide mercury + oxygen

Reactants Products

-Substance or molecule that -Substance that forms in a chemical
participates in a chemical reaction reaction
Atoms are not destroyed or created, so mass does not change during a chemical reaction.

C. Evidence of Chemical Change

Generally, evidence that a chemical change may be happening falls into one of four categories; you may observe more than one.
  1. Evolution of a gas- the production of a gas is often observed by bubbling or by a change in color
  2. Formation of a Precipitate- when two clear solutions are mixed and become cloudy, a solid precipitate has formed
  3. Release or Absorption of Energy- change in temperature of the giving off of light energy are signs of energy transfer
  4. Color Change in the Reaction System- look for a different color when two chemicals react

Vector : What is vector? in Physical and Mathematical Term

What is vector?
Vector is a quantity which poses magnitude as well as direction.

Examples of vector
Force, velocity etc.

What is free vector?
A vector which is permitted to move in anywhere in space according to their length and direction, is known as free vector.

What is bound vector or sliding vector?
It is a vector constrained to act along the given line is known as bound vector or sliding vector.

By www.Chemistrynotesinfo.blogspot.com
For mathematics for chemist

Transition state theory or Activated complex theory

Transition state theory or Activated complex theory

It is more modern theory proposed in 1932 by Pelzer & Manger later developed by Erying and colleagues.
1. Rate equation formation using the statistical mechanics to describe equilibrium between activated complex and reactant.
2. Rate equation formulation as per thermodynamical state function to describe transition state complex and reactant.
3. And rate equation 's statistical mechanical derivation.
Various postulates of Transition state theory or Activated complex theory are......
1. For any chemistry reaction to take place, it requires reactant have sufficient minimum energy. So it forms activated complex and reactant & complex are in equilibrium.
Reactant <~> [ activated complex ]
2. Activated complex have normal molecule with 4th degree of freedom along chemistry reaction coordinate.
3. And activated complex decompose along this 4th degree of freedom to yield products.
[Activated complex ] <~> Product
Overall,
             Transition state theory or Activated complex theory postulates says...
Reactant <~> [activated complex] <~> Product
Rate of reaction = decomposition rate of activated complex
Then,
         rate of reaction = probability of crossing energy barriers * concentration of activated complex at top of energy barrier * frequency of crossing energy barrier

Transition Metals in Periodic Table

Transition Series of Periodic Table for 11th 12th BSc Msc Chemistry

         What is Transition Metals?

As per IUPAC system, transition metals are the elements of periodic table which have partially filled d sub shell or gives cations with incomplete d sub shell, is called transition metal.
But many scientist says simply any metal which come in d block of periodic table is known as Transition Metal and these come in group 3 to 12 of the periodic table.          

         What is Inner Transition Metals?

f block elements are also considered as transition metals but they are a special type of transition metal so they named as Inner Transition Metals.

         what is electronic structure of transition metals?

Typical electronic structure (or electronic configuration) of transition metals atom can be written as the  [Inert gas] (n-1)d1-10n s1-2.

         Define different transition series?

First (3d) transition series present in 4thperiod of the periodic table.

Second (4d) transition series present in 5thperiod of the periodic table.

Third (5d) transition series present in 6thperiod of the periodic table.

Fourth (6d) transition series present in 7thperiod of the periodic table.

Chemistry 11th & 12th Formula in pdf

11th & 12th Classes Formula in PDF

Below is the list of Chemical Formulas Resources

1. Chemistry formulas for Atoms, Molecules and Chemical Arithmetic Part I

2. Chemistry formulas for Atoms, Molecules and Chemical Arithmetic Part II

3. Chemistry Formulas for Structure of Atom Part 1

4. Chemistry Formula for Atomic Structure Part 2

5. Chemistry Formulas for Nuclear Chemistry (Radioactivity)

6. Chemistry Formulas for Chemical Bonding


To download Chemistry 11th & 12th Classes Formula in PDF click on the download button below or just copy and paste the below link in your internet browser.



This above link contain pdf of formulas of  classes 11th and 12th and also of B.Sc and M.Sc formula and symbols. Read our notes to get first class result. With our first class notes and your hard work, you create your signing future by get selected in IIT, PMT, PAT, AIMS, PET, NET, GATE and many more entrance exams........

Some Basic Concepts of Chemistry Class 11 MCQ

Below is the List of all Chemical Formulas and Chemical Compounds

like inorganic compounds, biomolecules, chemical formulas, elements, alchemical substances, biomolecules, compounds, minerals, organic compounds, polyatomic ions, chemical compounds, chemical substances, alloys, alkanes.

Explain the type of Bonding

Types of Bond Formation
To attain stable inert gas electronic configuration three types of bonds are formed, which are described here by chemistry notes info..........
1. Ionic bonding
2. Covalent bonding
3. Coordinate covalent bonding

What is Adsorption ?

What is Adsorption ?

Adsorption: - The accumulation of molecular species at the surface rather than bulk of solid or liquid is called Adsorption.

Mechanism of Adsorption

Inside the Adsorbent (in bulk) the force acting between the particles are mutually balanced but on the surface, the particles are not surrounded by atoms or molecules of their kind on all sides and hence they posses attraction force so particle stick on the surface of the Adsorbent.
The extent of adsorption increases with increase in surface area per unit mass of the adsorbent at a given temperature and pressure.

Heat of adsorption: - With increase in heat Adsorption process decreases.

Adsorption equilibrium: -

                                     As the molecules of the adsorb ate are held on the surface of the solid adsorbent.
Entropy decreases, i.e. DS is negative
For the process of adsorption to occur, DG must be negative which is possible only when, DS keeps on decreasing and TDS keeps on increasing till ultimately DH becomes equal.
To TDS so that DG = 0, this state is called adsorption equilibrium.

Types of adsorption

There are two types of adsorption

        i.            Physical Adsorption or physisorption: -  

                                                                         If accumulation of gas on the surface of solid occurs on account of weak vanderwalls forces is called physical Adsorption.

      ii.            Chemical Adsorption or chemosorption: - 

                                                                         When gas molecules or atoms are held to the surface (solid) by chemical bonds, the Adsorption is called Chemical Adsorption.

1)      Lack of specificity: - A given surface of an Adsorbent does not show any preference for a particular gas as the vanderwalls forces are universal.
2)      Nature of Adsorbate: - The amount of gas Adsorbed by a solid depends on the nature of the gas.
3)      Reversible nature: - Physisorption is reversible because adsorbate may be removed by decreasing pressure.
4)      Surface area of Adsorbent: - Physisorption increases with increase in surface area.
5)      Enthalpy of Adsorption: - Physical Adsorption is exothermic process but its enthalpy of adsorption is low (20-40 KJ mol-1).
1)      High specificity: - It is high specific because it occurs if there is some possibility of chemical bonding.
2)      Irreversibility: - As chemisorptions involve compound formation, so it is usually irreversible process.
3)      Temperature: - Chemisorptions increases with increase in temperature after saturation starts decreasing.
4)      Pressure: - it is also increases with increase in pressure.
5)      Surface area: - chemisorptions increases with increase in surface area.
6)      Enthalpy of Adsorption: - Enthalpy of chemisorptions is high (80-240 KJ mol-1) as it involves chemical bond formation.
                                 The variation in the amount of gas Adsorbed by the adsorbent with pressure at constant temperature can be expressed by means of a curve termed as Adsorption isotherm.
 

Spin Multiplicity Rule

Definition of spin  Multiplicity Rule
According to spin Multiplicity Rule " transition between states of different multiplicity, S, are forbidden.
It is a selection rule for electronic transition in complexes. And another selection Rule is Laporte Selection Rule. 

Laporte Selection Rule

Definition of Laporte Selection Rule
According to Laporte Selection Rule " In a  molecule which has a  centre of symmetry, the transition between two symmetrical and unsymmetrical states are forbidden.  

Bent Rule

Definition of Bent Rule
As per bent Rule the more electronegative constituent prefer the hybrid orbitals having less s character & the more electropositive constituent prefer the hybrid orbitals having more s  character, is bent Rule.
jss
 

what is molarity ?

What is molarity? 

Molarity is also known as molar concentration, it is the ratio of moles of substance to volume in litre.
Where mole is weight in gram devided by molecular weight.
Molarity is chemistry terminology.

Molarity (M) :- 

                                No. of moles of the solute  / Volume of the solution in litre.
    M = strength in gram per litre / Molar mass of the solute
Unit =>   M = Moles/L

Molarity Chemistry Infographics
What is Molarity

 

DEBYE HUCKEL THEORY

Debye Huckel Theory

This theory is based on 3 assumptions that how the ions act in the solution

1. in the solution electrolytes completely dissossiate into ions

2. electrolyte solution are very dilute of order of 0.01M

3. each ion surrounded by ion of the opposite charge on the average.

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