Matter and its Nature
WEeb.in Team Science Total Views: 455 Posted: Sep 1, 2020 Updated: Oct 1, 2026
Matter and its Nature
- Matter exists in three different states in Physical Form
- Solids – Molecules are closely packed. It is structural rigidity to changes of shape or volume
- Liquids – Molecular Bonds in a liquid are weaker than those in a solid but stronger than those in gases
- Gases – Molecular Bonds in a gas are loosely held and weaker than those in solids and liquids
| v Boiling Point | The boiling point of a substance is the temperature at which the vapor pressure of the liquid equals the Atmospheric Pressure |
| v Melting Point | The temperature at which the solid exists in equilibrium with its liquid under an external pressure of one atmosphere. |
| v Evaporation | Evaporation is the process of a substance in a liquid state changing to a gaseous state due to an increase in temperature and/or pressure |
| v Freezing Point | Freezing point is the temperature at which a liquid becomes a solid at normal atmospheric pressure |
| v Surface Tension | Surface tension is the elastic tendency of a fluid surface which makes it acquire the least surface area possible |
| v Decantation | Is a process to separate mixtures by removing a liquid layer that is free of a precipitate. The purpose may be to obtain the liquid free from particulates or to recover the precipitate |
| v Specific Gravity | The ratio of the mass of a substance to the mass of a reference substance for the same given volume |
| v Filtration | Filtration is process that separate solids from fluids by adding a medium through which only the fluid can pass through |
| v Sublimation | Sublimation is the transition of a substance directly from the solid to the gas phase without passing through the intermediate liquid phase. |
| v Diffusion | Diffusion is defined as the movement of Gas into open space or diffusion into another gas |
| v Effusion | Movement of gas through a tiny hole is defined as effusion |
| v Emulsion | A fine dispersion of minute droplets of one liquid into another in which it is not soluble or miscible |
| v Viscosity | The state of being thick, sticky, and semi-fluid in consistency, due to internal friction |
| v Liquids at high altitudes boil at lower temperature due to low atmospheric pressure at high altitudes | |
| v Evaporation takes place only on the surface of Liquids | |
| v The melting point of Ice decreases with Increase in Pressure | |
| v Pure water has a maximum density of 1 gm/cm 3 at 4 Degrees Celsius | |
| v Surface Tension decreases with Increase in temperature | |
| v Spherical Shape of Liquid Droplets is due to the property of Surface Tension in Liquids | |
| v Boiling Point and Evaporation of a liquid differ in a basic point that Evaporation occurs at all temperatures whereas Boiling Point of a liquid occurs at specific Temperature | |
- All matter is made up of Atoms which is the smallest particle of the element that consists of three fundamental units – Protons, electrons and neutrons.
| v Discovery of Atomic Nucleus | v Ernest Rutherford based on Geiger–Marsden Gold Foil Experiment |
| v Discovery of Protons | v E Goldstein |
| v Discovery of Electrons | v J J Thomson |
| v Discovery of Neutrons | v James Chadwick |
- Nucleus is the center of the Atom contains the neutral charges Neutrons and Positively charged Protons, the electrons revolve around the nucleus of an atom
- Protons, electrons and Neutrons are called sub-atomic particle.
- Each sub-atomic particle has an anti-particle with an opposite electric Charge
- “Positron” is not a sub-atomic particle but an anti-particle of electron which has same mass as electron – 9.10 ×10-31Kg with opposite charge, whereas Proton is a sub atomic particle with mass 1.6726219 × 10-27Kg and positive Charge
- Atoms combine with each other to form compound atoms called Molecules
- John Dalton was the first scientist to use symbols for elements in a very specific sense.
- The most commonly used measurement for atomic radius is Nanometer – 0 x 10–9Metre and Angstrom A – 1.0 x 10-10Metre
- The relative Atomic Masses of all units have been measured w.r.t an atom of Carbon-12 which is equal to 1.66 × 10-24 g
- Hydrogen has the smallest atom and is considered to have an atomic mass – 1
- Molecules are defined as group of two or more atoms chemically bonded together, Atoms of same element or different elements group together to form a compound molecule.
- Compound formed between Atoms of Metals and Non-Metals have charged ions
| v Charge on the Ion – Negative | v Anion |
| v Charged on the Ion – Positive | v Cation |
- The combining capacity of an atom of an element with atoms of same element or different elements is called Valency of the element
| v Atomic Number | v Sum total of all protons present in the nucleus of an atom |
| v Atomic Mass | v Sum total of Protons and neutrons present in the nucleus of an Atom |
- The electrons present in the outermost shell of an atom are known as its valence electrons.
- Isotopes are atoms of same element having same Atomic Number but different Mass Numbers – (Hydrogen element has three Isotopes 1H1-Hydrogen, 2H1-Deuterium,3H1 – Tritium)
- Atoms of different elements with different Atomic Number but Same Mass Numbers are called Isobars. (Argon, Potassium, Calcium all have same Mass Numbers but different Atomic Number)
- Atoms of different elements, which have same number of neutrons but different atomic numbers, are called isotones.
- Avagadro Number: The number of Atoms present in 12g of Carbon of C-12 Isotope is 6.023 × 1023 Atoms
- 1 Mole of any substance will contain Avagadro number of Molecules or 6.023 × 1023 Atoms
- One Mole of any Gas at standard Atmospheric Pressure (STP) will have a volume of 22.4 Litres
- The electric neutrality of the atom is due to the presence of Equal number of Electrons and Protons in the atom
- The Spontaneous emission of radiation from the nucleus of an atom is a nuclear Phenomenon termed as Radioactivity
- Henry Becquerel first discovered radioactivity in 1896. The SI units to measure
- Radioactivity is Becquerel and unit of Becquerel is Second‑1(Second Inverse)
- The radiation dose absorbed by the human body is measured using the SI unit Gray or conventional unit RAD
- Carbon dating is a method for determining the age of an object containing organic material by using the properties of radiocarbon, a radioactive isotope of carbon.
- The most essential particle to continue the chain reaction in the fission of Uranium is Neutron.
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