Oxides are compounds of oxygen with elements, classified as acidic (non-metal), basic (metal), amphoteric, or neutral, which react with acids/bases to form salts and water. Salts are ionic compounds formed from these neutralization reactions, specifically when metal oxides (basic) react with acids or non-metal oxides (acidic) react with bases.
Key Types of Oxides and Their Behavior
Basic Oxides: Formed by metals (e.g.,
CuOcap C u cap O
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Isotopes are variants of a particular chemical element that have the same number of protons and electrons but differ in the number of neutrons in their nucleus. While having identical atomic numbers and almost identical chemical properties, they possess different atomic masses and physical properties. Examples include Carbon-12 and Carbon-14, both having 6 protons but different neutron counts.
Key Characteristics and Facts About Isotopes:
Structure: They share the same atomic number (protons) but have different mass numbers (protons + neutrons).
Chemical Behavior: Because they have the same electron configuration, they behave almost identical in chemical reactions.
Types:
Stable Isotopes: Do not emit radiation and do not change over time (e.g., Carbon-12).
Group 16 elements (oxygen, sulfur, selenium, tellurium, polonium) show distinct periodic trends: atomic radius, density, and metallic character increase down the group, while electronegativity, ionization enthalpy, and electron gain enthalpy decrease
Atomic radius is the measure of a neutral atom's size, typically half the distance between nuclei of identical bonded atoms, representing the distance from the nucleus to the outermost electron shell. Ionic radius is the size of an ion (charged atom), measuring the effective distance from the nucleus to the outer electron cloud in a crystal lattice
Electronegativity is the measure of an atom's ability to attract shared electrons in a chemical bond toward itself
In chemistry, a cation is an atom or molecule with a net positive electrical charge, formed when a neutral atom loses one or more electrons, resulting in more protons than electrons
In chemistry, an anion is an atom or molecule that has gained one…
An exothermic reaction is a chemical reaction in which energy is released to the surroundings. This energy is mostly released as heat, but sometimes also as light, sound, or electricity.
During a chemical reaction, old bonds break and new bonds form.
Breaking bonds requires energy
Forming new bonds releases energy
Burning, also called combustion, is a chemical reaction in which a substance reacts with oxygen and releases energy in the form of heat, light, and sometimes sound.
It is a chemical change
New substances are formed
Energy is always released
Elements: Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Caesium (Cs)
Atomic radius increases ↓(More electron shells added)
Reactivity increases ↓(Outer electron is farther from nucleus, easier to lose)
Melting point decreases ↓
An atom is the smallest particle of an element that can take part in chemical reactions and still keep the properties of that element.
Everything around you—air, water, food, metals, your body—is made of atoms. Atoms are extremely small; millions of atoms can fit across the width of a human hair.
An atom has a central nucleus and electrons moving around it. The structure can be compared to a solar system, where planets move around the Sun.
An atom is the smallest unit of matter that still keeps the properties of an element. Everything around us — air, water, plants, metals, and even our bodies — is made of atoms.
Atoms are extremely small and cannot be seen with the naked eye.
An atom has two main parts:
Nucleus (center of the atom)
A catalyst is a substance that speeds up a chemical reaction without being consumed or permanently changed in the process.
They lower the activation energy — the minimum energy required for a reaction to start.
This makes reactions faster and sometimes allows them to happen at lower temperatures.
They do not change the final products or the overall energy balance of the reaction.
Concentration in a chemical reaction refers to how much reactant is present in a certain volume of solution.
It tells you how many reacting particles (ions or molecules) are available in a given space.
A higher concentration means more reactant particles are packed into the same volume.
A lower concentration means fewer reacting particles are present.
Temperature is a major factor that controls how quickly a chemical reaction happens.
When temperature increases, particles gain more kinetic energy.
With more energy, particles move faster and collide more frequently.
These collisions are also more energetic, so more of them overcome activation energy.
As a result, the reaction speeds up noticeably when temperature rises.
Surface area is the total amount of the outside surface of a solid that is exposed to the surroundings. When you look at a solid object, its surface is the part that can touch or interact with other substances.
A large block has low surface area.
The same block crushed into tiny pieces has high surface area.
In chemistry, surface area is extremely important because reactions involving solids can only happen at the surface, where particles can meet and interact.
The rate of reaction indicates how fast reactants are transformed into products.
Reaction rates vary depending on conditions such as temperature, concentration, pressure, surface area, catalysts, and the nature of the reactants.
Faster reactions occur when particles collide more frequently and with sufficient energy.
The concept is explained by collision theory and activation energy.
The rate of reaction describes how quickly reactants are converted into products. Several conditions can speed up or slow down this process. Each factor works by influencing how often and how effectively particles collide.
Effect Increasing temperature raises the reaction rate; lowering temperature slows it down.
Reason At higher temperatures, particles move faster, collide more often, and more collisions have enough energy to overcome the activation energy barrier.
The rate of reaction is the speed at which a chemical reaction happens — how quickly reactants turn into products.
“Rate” simply means speed, so it describes how fast the reaction takes place.
Magnesium ribbon is a thin strip of the metal magnesium. It is light, shiny when cleaned, and reacts quickly with acids.
pH is a numerical scale that shows how acidic or alkaline (basic) a substance is. It ranges from 0 to 14.
pH 0–6: Acidic
pH 7: Neutral
pH 8–14: Alkaline (basic)
A metal carbonate is a compound made from:
a metal element, and
a carbonate group, which contains carbon and oxygen together.
A metal carbonate is usually a solid and often appears as a white or colored powder.
When a reactive metal reacts with a dilute acid, a salt is formed and hydrogen gas is released. This is one of the simplest ways to prepare a salt in basic laboratory chemistry.
Metal+Acid→Salt+Hydrogen gas\text{Metal} + \text{Acid} \rightarrow \text{Salt} + \text{Hydrogen gas}Metal+Acid→Salt+Hydrogen gas
Examples:
Magnesium + Hydrochloric acid → Magnesium chloride + Hydrogen
In chemistry, a salt is an ionic compound made of:
a cation (positively charged ion, usually from a base)
an anion (negatively charged ion, usually from an acid)
General form: Salt = cation⁺ + anion⁻
Example:
A more reactive metal replaces a less reactive metal from its salt solution.
Example: solid zinc + copper sulfate solution → zinc sulfate solution + solid copper
The solution may lose color, and a new metal may appear on the surface.
Commonly used to compare the reactivity of metals.
A displacement reaction happens when a more reactive element replaces a less reactive element in a compound.
General pattern: Element A + Compound of B and C → Compound of A and C + Element B.
Elements have different reactivities.
A more reactive element can push out a less reactive one.
A list of metals arranged in order of how reactive they are.
Most reactive at the top, least reactive at the bottom.
Helps predict reactions with water, acids, and oxygen.
Potassium, Sodium, Calcium, Magnesium, Aluminium , Carbon, Zinc, Iron, Hydrogen, Copper, Silver, Gold.
When a metal reacts with a dilute acid, it usually produces:
A salt (depending on the acid)
Hydrogen gas (H₂)
General equation: Metal + Acid → Metal Salt + Hydrogen gas.
Potassium , Sodium, Lithium
potassium is the most reactive of the three
Sodium is the second most reactive
Lithium is the least reactive
The most reactive metal with oxygen is caesium, followed closely by other alkali metals like potassium and sodium.
Lustrous means having a shine or glow, or being shiny and reflective.
Metals typically exhibit properties like malleability, ductility, high density, high melting/boiling points, and excellent conductivity for heat and electricity.
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Many metals react with oxygen if they get hot enough. we have seen magnesium react with oxygen when you heat it.
An exothermic reaction is a chemical or physical process that releases energy, most commonly as heat, into its surroundings.
Enthalpy change (\(\Delta H\)) is the heat absorbed or released by a system during a process at constant pressure.
A neutralization reaction is a chemical reaction between an acid and a base that produces a salt and water.
Mixing epoxy resin and hardener is a chemical reaction called polymerization, where a liquid two-part epoxy system cures into a solid, rigid material through a process called cross-linking
A strong acid completely ionizes in water to produce a large amount of hydrogen ions (\(H^{+}\)), while a weak base only partially ionizes in water, creating fewer hydroxide ions (\(OH^{-}\)).
Some chemical reactions take heat from their surroundings and store it as chemical energy.
Those are are called endothermic reactions.
When endothermic reaction takes place temperature decreases.
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Sodium hydrogencarbonate + citric acid -> Sodium citric + water + carbon dioxide
What are Exothermic reactions
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Exothermic reactions are chemical processes that release energy, typically as heat, into the surroundings.
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The equation of potassium with water is
potassium + water --> potassium hydroxide + hydrogen
Keshu, You know a chemical reaction is finished when there are no more observable changes like color change or bubbling, the amount of precipitate stops forming, or the total mass remains constant. i did understand this point.
Burning releases exothermic reaction
An exothermic reaction is a chemical or physical process that releases energy, typically as heat, light, or sound, into its surroundings.
A chemical bond is the attractive force that holds atoms, ions, or molecules together to form a compound.
An attractive force is a force that causes objects or particles to move toward each other.
Combustion is a rapid chemical reaction between a substance, called a fuel, and an oxidant, usually oxygen, that releases energy as heat and light, often with a flame.
An oxidant, also called an oxidizing agent, is a chemical substance that accepts electrons from another substance during a chemical reaction.
Group 7- the halogens
fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At).
The melting point of the halogens top to bottom decreases because as you move down, the atoms get larger and heavier, leading to stronger van der Waals force between the diatomic molecules, requiring more energy to melt or boil.
Van der Waals forces are weak, short-range electrostatic attractions between neutral atoms or molecules.
Electrostatic attraction is the force of attraction between two oppositely charged particles, like a positive and a negative charge.
The four fundamental forces are gravity, the electromagnetic force, the strong nuclear force, and the weak nuclear force.
What are atoms like
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Atoms are made up of three kinds of particles: protons, neutrons, electrons.
These particles are arranged in a similar way in every atom
The protons and neutrons are tightly packed in the center. There they form the nucleus of the atom.
The electrons orbit the nucleus around it.
What happens if the electron number increases or decreases? And same with the neutron
A chemical reaction happens when one or more substances change into completely new ones. The particles of the reactants rearrange their atoms to form new bonds, creating products with different physical and chemical properties. For example:
2H2+O2→2H2O2H_2 + O_2 → 2H_2O2H2+O2→2H2O
Here, hydrogen and oxygen (gases) react to form water (a liquid) — totally new properties!
Reactants → the starting substances (what you begin with).
Only 2 research topic.
No mention of Santhosh Ji's work
Atomic research and respiration is not a specific topics
atoms are the smallest building blocks of all substances around us
they combine to form molecules (like h2o= water, o2= oxygen gas
Physical changes require energy for processes like melting, or evaporation.
Physical changes often involve transitions between solid, liquid, gas
Solid-> liquid : ice melting
Liquid-> Gas: Water boiling
Solid-> Gas: Dry ice sublimation
Chemical changes produce substances with new chemical identities.
neatly written in 4line copy book. keep it up keshu.
content is good and satisfying.
Symbol: H
Atomic number: 1
Color: Colorless
Gas: Yes
keywords
Atomic number 1
Most abundant element
Diatomic molecule (H₂)
Fuel cell
Hydrogen bonding
Isotopes (protium, deuterium, tritium)
Combustion
Electrolysis
Renewable energy
Atomic number 2
Noble gas
Inert gas
Low boiling point
Cryogenics
MRI cooling
Balloon gas
Helium-3 and Helium-4 isotopes
Non-flammable
Atomic number 8
Diatomic molecule (O₂)
Essential for respiration
Oxidation reactions
Ozone (O₃)
Electron acceptor
Combustion supporter
Photosynthesis
Air composition
Your body needs about 21% oxygen to function.
Helium has zero oxygen. So breathing it is like sitting in a room full of invisible poison gas.
First signs: headache, dizziness, confusion → then unconsciousness → death in minutes.
Why is helium considered dangerous despite being non-toxic?
How does inhaling helium affect the brain and body within seconds?
Why is it more dangerous to inhale helium from a tank than a balloon?
What safety measures should be in place during helium use in science or entertainment?
Diamonds might look fancy and expensive, but at their core, they’re made of something super basic: carbon. Yeah — the same stuff inside a pencil. So what makes a diamond different? It’s all about where and how it forms.
Way deep under the Earth’s surface — we’re talking about 100 to 200 kilometers down — the pressure is insane and the heat is crazy high. Down there, carbon gets squeezed so tightly for millions (or even billions) of years that the atoms lock into a super strong structure. That’s what forms a diamond.
Then one day, a volcanic eruption happens, and boom — those diamonds ride up to the surface through special pipes called kimberlite pipes. That’s how they end up where we can find them.
Diamonds are:
The hardest natural material on Earth (nothing can scratch them except other diamonds).
Super good at handling heat, so they’re even used in some electronics…
YOU can include a video keshu