The correct answer is Element.

Key Points

Element

• It is a substance that cannot be further resolved into simpler substances by chemical means.
• It is a substance that is made entirely from one type of atom.
• For example, Hydrogen, Carbon, Gold etc.

Compound

• It is a substance made of more than one type of atom.
• It is a substance made from two or more different elements that have been chemically joined
• For example, H₂O), NaCl, CaCO₃

The correct answer is Actinium.

Key Points Actinium:

• It was discovered in the year 1899 by Andrew Debierne.
• He extracted it from the uranium ore pitchblende (uranium oxide, U3O8) which occurs in trace amounts.
• Actinium is a soft, silvery-white radioactive metal, it glows blue in the dark because its intense radioactivity excites the air around it.
• Actinium is a very powerful source of alpha rays but is rarely used outside research.
• Actinium used for research purposes is made by the neutron bombardment of radium-226.
• Actinium also occurs naturally in uranium ores.

Nobel Gasses:

• Inert gases are nonmetals placed at the extreme right end of the periodic table.
• They all together form the 18th group of the period table.
• They have a stable electronic configuration i.e., all of their electronic orbitals are completely filled.
• Nobel gasses are a group of chemical elements that do not interact with other elements in a manner.
• General because their electron orbits are complete and filled with electrons.
  • ​Helium, Neon, Argon, Krypton, Xenon and Radon.
  • These elements are in the eighteenth groups of the periodic table.
  • Nobel gasses contain 0.93% of the atmospheric volume and 1.29% of its mass.​

​​

Important PointsProperties of Nobel Gasses:

• ​​Show as gases in room conditions.
• No colour and no smell.
• Have 8 electrons equivalent.
• Produce vehicles only in special circumstances.
• It is drawn from the air in liquefaction and distillation.
• Found in the form of single-atom gases.
• The very weak internal attraction between their atoms.
• It has very low melting and boiling grades.

Electronic Configuration of Noble gases.

• He = 1s2
• Ne = [He]2s22p6
• Ar = [Ne]3s23p6
• Kr = [Ar]3d104s24p6
• Xe = [Kr]4d105s25p6
• Rd = [Xe]4f145d106s26p6

Additional Information

• Xenon(Xe) gas is also known as stranger gas.
• It is called 'STRANGER GAS' because the word 'XENON' means 'STRANGE' in Greek.
• The noble gas Xenon possesses the highest melting point.
• It was discovered by William Ramsay and Morris Travers in 1898.
• It is more than 4.5 times heavier than air.
• xenon is colorless, odorless, and tasteless.
• It is used in instruments for radiation detection.

The correct answer is Emulsification.

Key Points

• Soap removes grease by the process of Emulsification.
• Emulsification:
  • Emulsification is the process of dispersing two or more immiscible liquids together to form a semistable mixture.
  • In food applications, these two liquids generally consist of an organic (oil) phase and an aqueous (water) phase that is stabilized by the addition of a food-grade emulsifier (surfactant).
  • The most general emulsions are of the oil-in-water (O/W) type.
  • Examples of food emulsions include mayonnaise, sauces, ice cream, and milk.
  • Water-in-oil (W/O)-type emulsions are less common in food applications, with the most prominent example being butter, which is an emulsion of water dispersed in milk fat.

Additional Information

• Coagulation:
  • Coagulation, generally known as clotting, is the process by which blood changes from a liquid to a gel, forming a blood clot.
  • It potentially results in hemostasis, the cessation of blood loss from a damaged vessel, followed by repair.
• Adsorption:
  • Adsorption is the adhesion of atoms, ions or molecules from a gas, liquid or dissolved solid to a surface.
  • This process creates a film of the adsorbate on the surface of the adsorbent.
  • This process differs from absorption, in which a fluid is dissolved by or permeates a liquid or solid.
• Osmosis:
  • Osmosis is the spontaneous net movement of solvent molecules through a selectively permeable membrane into a region of higher solute concentration, in the direction that tends to equalize the solute concentrations on the two sides.

The correct answer is Reduces moisture content which inhibits the growth of microorganisms.

Explanation:

• Provides an acidic environment to kill microorganisms: Salt itself does not provide an acidic environment. However, pickles are often made using an acidic solution such as vinegar, which is responsible for creating an acidic environment that helps preserve the pickles.
• Salt is commonly used as a preservative in pickles due to its ability to reduce moisture content. When salt is added to pickles, it draws out the water from the food through the process of osmosis.
• This reduction in moisture inhibits the growth of microorganisms such as bacteria, yeasts, and molds that require moisture to thrive. By creating an environment with lower moisture levels, salt helps to prevent spoilage and extend the shelf life of pickles.
• Cuts off the air so that microorganisms cannot enter: While oxygen can contribute to the spoilage of certain foods, the use of salt in pickles is primarily focused on reducing moisture content rather than cutting off air.
• contains chemicals that kill microorganisms: Salt itself does not contain specific chemicals that kill microorganisms. However, the process of osmosis, which occurs when salt is added to food, can have a dehydrating effect on microorganisms and inhibit their growth.

The correct answer is  CaO.

Key Points

• Calcium oxide, commonly known as quicklime or burnt lime, is a widely used chemical compound.
• It is a white, caustic, alkaline, crystalline solid at room temperature.
• Quicklime is known to be fairly caustic and alkaline under standard conditions.
• Quicklime is known to be an irritant to the eyes and the skin.
• It is advisable to use a full personal protective equipment kit while handling this compound (including goggles, head hood, polyurethane and rubber gloves, cotton work suit, and leather boots).

The correct answer is Tartaric acid

 Key Points

• Naturally occurring acids that occur naturally in foods.
• Food acids are the important acids found in natural food products that give them a distinct flavor or a tinge.
• The human body tends to react differently to different types of food acids.
• There are different types of food acids like citric acid, malic acid, and tartaric acid that are naturally occurring food acids.

 Additional Information

The correct option is Liquid.Key Points

•  The state of matter that has definite volume but cannot form a definite shape is liquid.
• The liquid is the second state of matter.
• The particles or atoms in a liquid compound are not closely packed.
• It cannot form a definite shape like solids.
• It can be measured in volume.
• The particles in liquid compounds are away from each other.

Additional Information

•  Gas is the third state of matter.
• It cannot form a definite shape and volume.
• The particles in gaseous compounds are far away from each other.
• Solid is the first state of matter and has a particular shape.
• Solid compounds have close packing of atoms.
• Plasma is the fourth state of matter.

The correct option is Line and dots.

Key Points

•  In Lewis structure, the bonding between atoms of chemical compounds is shown by lines and dots.
• The lewis structure is the schematic denotation of the valence electrons of a molecule in the form of dots and lines.
• The bonding between the atoms of a  molecule is represented as lines.
• The unshared electrons in the molecule are represented in the form of dots.
• the lewis structure of chemicals compound is discovered by a scientist named Gilbert N. Lewis.

Additional Information Spheres.

• The sphere is a notation of an atom in a structure in a round or circular manner.
• In the sphere form structure, we cannot see the bonding within atoms clearly.

Wedge bonds.

• The wedge bonds in a chemical compound are shown in a bold triangular pointed manner.
• it is a bond representing the position of an atom near the viewer's side.​

Ball and sticks.

• The atoms and bonding in a compound are represented in the form of balls and sticks.
• The atoms are denoted by a circular ball shape spherical structure.
• The bonds are denoted by sticks.
• We can see clear bonding within the structure.

Key Points

• A British physicist J.J.Thomsom Heightened the theory of Dalton.
• Thomson found the existence of extremely minute particles inside the atom.
• He compared the atom with a 'watermelon' in which the Red part resembles the positively charged portions while the black seed resembles the negatively charged electrons.
• The atom itself is neutral in nature, as it has equal positive and negative charged electrons.
• Thomson discovered 'Electrons' for which he got Nobel prize in 1906 A.D.
• Thomson proposed a better atomic theory than Dalton's atomic model.
• According to him, a positive charge is dispersed everywhere and the idea that atoms are made up of negative electrons embedded in a gel of positive charge was wrong.
• Electrons were accidentally discovered by J. J. Thomson while studying the cathode rays.
• The name electron was given by 'stony'.
• Cathode rays are emitted from the cathode in a straight line if these rays strike on metal objects there is the formation of 'X-rays'.

Additional Information

James Chadwick-

• Sir James Chadwick was awarded the 1935 Nobel Prize in Physics for his discovery of the neutron in 1932.
• By 1920, physicists knew that most of the mass of the atom was located in a nucleus at its center and that this central core contained protons.
• In May 1932 James Chadwick announced that the core also contained a new uncharged particle, which he called the neutron.

• Rutherford overturned Thomson's atom model in 1911 with his well-known Gold Foil experiment.
• Rutherford made an experiment, he beamed alpha particles through a thin gold foil. From this, he came to know that:
  • Most alpha particles passed through the gold foil, very few particles bounced back exactly towards the source.
  • Some of the particles deviate at various angles.
  • He concluded that an atom has a tiny, dense, 'positively charged' core, where all mass is concentrated; known as Nucleus.
  • The thickness of gold foil - 0.00004 cm.
  • Alpha particle - A helium nucleus.

• In 1803 A.D. he put forth his famous atomic theory.
  • The matter is made up of small particles called atoms.
  • Atoms can not be created, divided into smaller particles, nor destroyed in the chemical process.
  • Atom is a rigid and massive ball-like structure.

The chemical name of Chloroform is Trichloromethane.Key Points 

• Chloroform or Trichloromethane (CHCl3) is a colorless, dense, and non-flammable liquid that is produced on a large scale as a precursor to PTFE (Teflon) and refrigerants.
• It has a somewhat sweet taste and a pleasant smell, and it was used as an anesthetic in the 19th and early 20th century, but it was banned for this use due to its harmful health effects.

Additional Information 

• ​Acetic Acid: Its chemical formula is CH3COOH. It is a colorless liquid organic compound that gives vinegar its sour taste and pungent smell.
  • It's used in the production of chemicals and for food preservation.
• Calcium Carbonate: Its chemical formula is CaCO3. It's a white insoluble solid occurring naturally as chalk, limestone, marble, and forming mollusk shells and stony corals.
• Sodium Bicarbonate: Its chemical formula is NaHCO3. It's a white crystalline solid, but often appears as a fine powder.
  • It has a slightly salty, alkaline taste resembling that of washing soda (sodium carbonate). The natural mineral form is known as nahcolite. Sodium bicarbonate is commonly known as baking soda.

The correct answer is They have low boiling points.

Key Points

• Group 17 elements, also known as halogens, include fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At).
• Halogens have distinct characteristics that define their behavior and properties.
• The characteristic property of halogens in Group 17 will be identified.
• Halogens in Group 17 have low boiling points compared to many other elements.
• The low boiling points are due to the weak intermolecular forces between halogen molecules, which are primarily van der Waals forces.
• Halogens exist as diatomic molecules in their elemental form (e.g., F2, Cl2, Br₂, I2), and the weak forces between these molecules result in relatively low boiling points.
• The boiling points of halogens increase down the group from fluorine (F) to iodine (I) due to the increase in the size and molecular weight of the atoms.
• While halogens are not good conductors of electricity in their elemental form, they can participate in redox reactions and readily accept an electron to form negative ions.
• Halogens are not abundant in the Earth's crust. They are more common in the form of compounds rather than as pure elements.

Additional Information

• Halogens are highly reactive nonmetals.
• They have seven valence electrons in their outermost energy level, resulting in a strong tendency to gain one electron to achieve a stable electron configuration.
• Halogens readily form negative ions (anions) by accepting an electron to complete their octet, rather than forming positive ions (cations).
• Halogens are often found in compounds such as metal halides (e.g., sodium chloride, NaCl) or organic halides (e.g., chloroform, CHCl₃).
• They exhibit a range of colors, with fluorine being pale yellow, chlorine greenish-yellow, bromine red-brown, and iodine purple.

The correct option is triple point.

CONCEPT:

• The temperature and pressure at which the solid, liquid, and vapor phases of a pure substance coexists in equilibrium are called the triple point.​
• The Triple point is a line on the P-V diagram where all the three phases solid, liquid, and gases exist in equilibrium.
• The triple point is merely the point of intersection of the sublimation and vaporization curves.
• It has been found that on a ‘p-T’ diagram the triple point is represented by a point and on a ‘p-v’ diagram it is a line, and on a ‘u-v’ diagram it is a triangle.
• In the case of ordinary water, the triple point is at a pressure of 4.58 mm Hg and a temperature of 0.01°C.
• The matter solidifies on the left side of the triple point, not at the triple point.
• The matter liquifies on the upper side of the triple point, not at the triple point.
• The matter sublimates on the right side of the triple point, not at the triple point.

correct answer is Gallium

Key Points

Elements and their symbol:

• An element is a  naturally occurring pure substance made up of the same type of atoms.
• They have identical nuclei consisting of the same number of protons.
• There are 118 elements found in nature and are arranged in a table according to their atomic number known as the periodic table.
• The elements are represented by their symbols.
• Each element has a unique symbol and some of the symbols are derived from their Latin names such as Au for Gold from Aurum, Pb for the lead from Plumbum.
• The periodic table shows us all the elements and their symbols.

Explanation:

• Gallium is a chemical element with the symbol Ga and atomic number 31.
• Gallium is a soft, silvery metal, which is liquid at standard temperature and pressure. 
• Properties of Gallium:
• Atomic Number: 31
• Group Number: 13
• Gl, G, Gm these do not belong to any elements.

The correct answer is CO2.

Key Points

• Ionic bonds occur when there is a complete transfer of electrons from one atom to another.
• This usually happens between a metal and a nonmetal atom.
• The atom that loses an electron becomes a positively charged cation, and the atom that gains an electron becomes a negatively charged anion.
• The oppositely charged ions are attracted to each other, forming an ionic bond.
• Carbon Dioxide consists of one Carbon atom (a nonmetal) and two Oxygen atoms (also a nonmetal).
• In this molecule, the Carbon atom shares electrons with the Oxygen atoms, forming covalent bonds. Therefore, CO2 does not form an ionic bond.

Additional Information

 NaCl (Sodium Chloride):

• Sodium Chloride is formed by an ionic bond.
• Sodium (a metal) donates an electron to Chlorine (a nonmetal), forming a positively charged Sodium ion and a negatively charged Chloride ion.
• The electrostatic attraction between these oppositely charged ions forms the ionic bond.

MgO (Magnesium Oxide):

• Magnesium Oxide is also formed by an ionic bond.
• Magnesium (a metal) donates two electrons to Oxygen (a nonmetal), forming a positively charged Magnesium ion and a negatively charged Oxide ion.
• The attraction between these ions forms the ionic bond.

KI (Potassium Iodide):

• Potassium Iodide is formed by an ionic bond as well.
• Potassium (a metal) donates an electron to Iodine (a nonmetal), forming a positively charged Potassium ion and a negatively charged Iodide ion.
• The ionic bond is formed due to the attraction between these ions.

Key Points

"color: rgb(33, 37, 41); --darkreader-inline-color: #d1cdc7;">

• Isotones: These are the atoms of different elements having the same number of neutrons.
  • Examples: 146C, 157N
  • The number of neutrons in Carbon and Nitrogen is 8.

• Isobars: These are atoms of the elements having the same atomic mass but different atomic numbers.
  • Examples: 4018Ar, 4020Ca
  • In the case of Ca and Ar atomic mass of both the element is 40.
• Isotopes: These are atoms of the elements having the same atomic number but a different mass number.
  • Examples: 126C, 136C
  • Both elements have the same no of protons means the same atomic number.
• Isoelectronic: These are the atoms/molecules/ions containing the same number of electrons.
  • Examples: N3–, O2–, F–

The correct answer is 3 

Key Points

• Valency
  • The outermost electron shell of an atom is called the valence shell.
  • The electrons present in the outermost shell of an atom are called valence electrons.
  • The valence electron of an atom takes part in a chemical reaction because they have more energy than all the inner electrons.
  • The combining capacity of an atom of an element to form a chemical bond is called its valency.
• The valency of an element is
  • Equal to the number of valence electrons
  • Equal to the number of electrons required to complete eight electrons in the valence shell.
  • Valency of a metal=No. of Valence electrons
  • Valency Of a non-metal=8-No. of valence electrons

Additional Information

Valency table for some important elements:

The correct answer is Photon.

Key Points

• Electrons, Protons, and Neutrons constitute an atom.
• The nucleus of an atom contains protons and neutrons that are orbited by electrons.
• Protons and neutrons have nearly equal masses, but they differ in charge.
• The mass number of an atom is equal to the total number of protons and neutrons.
• The number of protons within the nucleus of a given atom is equal to the atomic number of the corresponding element.
  • For example, the atomic number of helium is two. Therefore, the number of protons is also two.
• The number of neutrons within the nucleus of a given atom can be found by subtracting the atomic number from the atomic mass i.e difference between the mass number of the atom and the atomic number.

The correct answer is Strontium.

Key Points

• The volatile metal compounds of copper, calcium, and strontium are generally used in fireworks to get colours.
• This is because these metals have low ionisation enthalpies.
• Strontium Carbonate imparts red colour, Calcium Chloride imparts orange colour, and Copper Chloride imparts blue colour.
• A firecracker contains a fuel charcoal, sulfur and potassium nitrate -similar to gunpowder.
• When the firework explodes, the metal particles start oxidizing and heat is produced.
• This heat excites the metal particles and colourful light depending on the metal is emitted.
• Enthalpy is the total sum of the internal energy and the product of the pressure and volume of a thermodynamic system.
• Ionization energy is the energy that is required to remove an electron from its orbit to a point where it is no longer associated with that atom

The correct answer is Both 1 and 2.

Key Points

​Rutherford’s scattering experiment:

• In this experiment, the scattering of particles is explained with the concept of coulombs interaction between the atoms.
• He shows that in the middle of the atom, highly dense particles are present in the center of the atom, which is named the nucleus.
• So, from the scattering experiment, the credit for the discovery of the nucleus goes to the scientist named Rutherford in the year 1911.
• In the nucleus, concentrated charged particles are present, they are protons and neutrons.
• Thus, Rutherford’s scattering experiment led to the discovery of the nucleus in the atom.

Isotopes

• Isotopes are atoms of the same element; they have the same atomic number but different mass numbers.
• Isotopes have a different number of neutrons in their nucleus.
• Hence, both statements are correct.

The correct answer is Oxidizing.

Key Points

• Potassium permanganate (KMnO₄) is a strong oxidizing agent that oxidizes dissolved impurities from water such as iron, manganese, and hydrogen sulfide (H₂S) by converting them into solid particles.
• These impurities are then filtered out of the water.
• It is a salt consisting of K⁺ and MnO^{− 4} ions.
• It is a strong oxidizing agent.
• It is used as a medication for cleaning wounds and dermatitis.

​Additional Information

• Some other chemical disinfectants used for water:
  • Hypo chloride
  • Chlorine dioxide
  • Chlorine
  • Hydrogen peroxide
  • Potassium permanganate
  • Gamma rays
  • Ultraviolet light

The correct answer is Zinc and Copper.

Key Points

• Brass is an alloy of copper and zinc, in proportions which can be varied to achieve varying mechanical, electrical, and chemical properties. 
• It is a substitutional alloy: atoms of the two constituents may replace each other within the same crystal structure.

Additional Information Brass Properties

• Brass often has a bright gold appearance, however, it can also be reddish-gold or silvery-white. A higher percentage of copper yields a rosy tone, while more zinc makes the alloy appear silver.
• Brass has higher malleability than either bronze or zinc.
• Brass has desirable acoustic properties appropriate for use in musical instruments.
• The metal exhibits low friction.
• Brass is a soft metal that may be used in cases when a low chance of sparking is necessary.
• The alloy has a relatively low melting point.
• It's a good conductor of heat.
• Brass resists corrosion, including galvanic corrosion from saltwater.
• Brass is easy to cast.

The correct answer is Oxygen and Water.

Key Points

• The presence of both oxygen and water or water vapor is essential for rusting.
  • Rust is formed from the reaction between oxygen and iron in an environment containing water vapour.
  • Rusting is an oxidation reaction. The iron reacts with water and oxygen to form hydrated iron(III) oxide.
  • Iron + Water + Oxygen → Hydrated iron(III) oxide.
  • 4Fe + 3O2 + 6H2O → 4Fe(OH)3

correct answer is Centrifugation

Key PointsCentrifugation:

• In dairies, the process of Centrifugation is used for this process.
• The milk to be skimmed is put in a closed container in a big centrifuge machine.
• When the centrifuge machine is switched on, the milk starts rotating at a very high speed in this container.
• Due to this, the milk separates into ‘cream’ and ‘skimmed milk’.
• The cream being lighter floats over the skimmed milk and can be removed.

Additional Information

The correct answer is Diamond.

Key Points

• The hardest known substance available naturally on earth is Diamond.
• Diamond is composed of pure carbon and the atomic bonding of the atoms makes it the hardest material.
• In diamond, every layer of carbon atom is bonded with strong sigma bonds.
• The presence of such strong covalent bonding between the carbon atoms arranged in a tetrahedral manner imparts rigidity to the substance making it the hardest known substance.

Important Points

• Industrial diamonds have three varieties
  •  'ballas' which is a mass of minute diamond crystals difficult to cleave
  •  'bort' is yellowish-grey to a black colour and massive, flawed, or irregular in shape
  • 'carbonado' is black, very hard opaque, and without cleavage.
• Diamond occurrences in India have been reported since prehistoric times.
• Presently, the diamond fields of India are grouped into four regions
  • South Indian tract of Andhra Pradesh, comprising parts of Anantapur, Kadapa, Guntur, Krishna, Mahabubnagar, and Kurnool districts
  • Central Indian tract of Madhya Pradesh, comprising Panna belt​
    • Panna is famous for diamond mines.
    • It is Asia's biggest and only active diamond mine.
    • The mine is run by the National Mineral Development Corporation.
  • Behradin-Kodawali area in Raipur district and Tokapal, Dugapal, etc. areas in Bastar district of Chhattisgarh
  • Eastern Indian tract mostly of Odisha, lying between Mahanadi and Godavari valleys.
  • Hindustan Copper Ltd. at Maubhandar smelter in Singhbhum district of Jharkhand obtains silver from copper slimes.

The correct answer is ​They are gases at room temperature
Key Points

• The elements in Group 1 of the Periodic Table are known as alkali metals.
• These include elements like Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs), and Francium (Fr).

Properties of these elements:

a. They are good conductors of electricity - TRUE:

• alkali metals are good conductors of electricity.
• This is due to their ability to easily lose their outermost electron to form positive ions.
• The delocalized electrons are free to move, allowing electric current to pass through.

b. They are highly reactive - TRUE:

• Alkali metals are known for their high reactivity.
• This is because they have only one electron in their outermost shell, and they want to lose this electron to achieve a stable electron configuration (a full outer shell).
• This makes them highly eager to participate in chemical reactions.
• For instance, they react vigorously with water to produce hydrogen gas and alkali hydroxides.

C. They have one valence electron - TRUE:

• The defining characteristic of alkali metals is that they each have a single electron in their outermost energy level (also known as valence shell).
• This single electron is held relatively loosely because it is far from the positive charge of the nucleus, making it easy for alkali metals to lose this electron and form a positive ion.

d. They are gases at room temperature - FALSE:

• None of the alkali metals are gases at room temperature.
• They are all solid at room temperature.
• The elements that are gases at room temperature are located in the rightmost area of the Periodic Table, such as the noble gases (Group 18).