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🇮🇳 ISC Class 11 · flashcards
ISC Class 11 Chemistry Flashcards
56 question-and-answer cards covering Chemistry as it is examined in ISC Class 11. 24 of them are printed below, taken from across the deck — no signup, no paywall on the preview.
24 sample cards from the Chemistry deck
Sampled from the end of the deck, so these are different cards from the ones shown on the syllabus page.
What are valence electrons?
The electrons present in the outermost shell of an atom, which take part in chemical bonding and determine the valency of the element.
State the octet rule.
Atoms tend to gain, lose, or share electrons to achieve a stable configuration of eight electrons in their valence shell (a noble gas configuration).
Define ionic (electrovalent) bond.
A bond formed by the complete transfer of one or more electrons from one atom to another, resulting in oppositely charged ions held together by electrostatic attraction. Example: NaCl.
What conditions favour the formation of an ionic bond?
Low ionization enthalpy of the metal, high (negative) electron gain enthalpy of the non-metal, high lattice enthalpy, and a large electronegativity difference between the atoms.
Define covalent bond.
A bond formed by the mutual sharing of one or more pairs of electrons between two atoms. Example: H2, Cl2, CH4.
Distinguish between single, double, and triple covalent bonds.
Single bond shares one electron pair (1 sigma), double bond shares two pairs (1 sigma + 1 pi), triple bond shares three pairs (1 sigma + 2 pi). Bond strength increases and length decreases from single to triple.
Define bond length and bond enthalpy.
Bond length is the equilibrium distance between nuclei of two bonded atoms. Bond enthalpy is the energy required to break one mole of a particular bond in the gaseous state.
Define bond order and bond angle.
Bond order is the number of bonds between two atoms in a molecule. Bond angle is the angle between two adjacent bonds at the central atom.
What is a coordinate (dative) covalent bond?
A covalent bond in which the shared pair of electrons is contributed by only one of the two atoms. Example: NH4+ and the bond in O3.
What is a Lewis (electron dot) structure?
A representation of a molecule showing the bonding pairs and lone pairs of valence electrons as dots/lines around the symbols of atoms.
What is formal charge and how is it calculated?
Formal charge = (valence electrons) - (non-bonding electrons) - 1/2(bonding electrons). It helps identify the most stable Lewis structure.
What makes a covalent bond polar?
A difference in electronegativity between the bonded atoms causes unequal sharing of electrons, creating partial positive and negative charges. Example: HCl.
Define dipole moment and give its unit.
Dipole moment (mu) = charge x distance of separation; it measures bond/molecular polarity. Unit is the Debye (D); it is a vector quantity.
Why is CO2 nonpolar despite having polar bonds?
CO2 is linear and symmetrical, so the two equal and opposite C=O bond dipoles cancel out, giving a net dipole moment of zero.
What is the main postulate of VSEPR theory?
Electron pairs (bonding and lone) around a central atom repel each other and arrange themselves to minimize repulsion, giving the molecule a definite shape.
What is the order of repulsion strength between electron pairs in VSEPR theory?
Lone pair-lone pair > lone pair-bond pair > bond pair-bond pair.
Using VSEPR, give the shapes of CH4, NH3, and H2O and their bond angles.
CH4 is tetrahedral (109.5 degrees); NH3 is trigonal pyramidal (107 degrees); H2O is bent/angular (104.5 degrees). Lone pairs reduce the angle.
What is hybridization?
The intermixing of atomic orbitals of slightly different energies to form an equal number of new, equivalent hybrid orbitals with definite geometry.
Give the geometry associated with sp, sp2, and sp3 hybridization.
sp is linear (180 degrees), sp2 is trigonal planar (120 degrees), and sp3 is tetrahedral (109.5 degrees).
What are the three states of matter and how do they differ in intermolecular forces?
Solid (strong forces, fixed shape and volume), liquid (moderate forces, fixed volume but no fixed shape), gas (negligible forces, no fixed shape or volume).
Define surface tension and viscosity (properties of the liquid state).
Surface tension is the force per unit length acting on the surface of a liquid, minimizing surface area. Viscosity is the resistance to the flow of a liquid due to internal friction between layers.
How do surface tension and viscosity vary with temperature?
Both surface tension and viscosity decrease with an increase in temperature, because higher kinetic energy weakens intermolecular attractions.
What is vapour pressure and how does it relate to boiling point?
Vapour pressure is the pressure exerted by a vapour in equilibrium with its liquid at a given temperature. A liquid boils when its vapour pressure equals the external (atmospheric) pressure.
List the main types of bonding/intermolecular forces.
Ionic bond, covalent bond, metallic bond, and intermolecular forces such as London dispersion forces, dipole-dipole interactions, and hydrogen bonding.
What this deck covers
The Chemistry deck follows the ISC Class 11 Chemistry syllabus — 5 chapters and 22 topics — so questions land on material that is genuinely examinable rather than trivia around it. That works out to roughly 11.2 cards per chapter.
Answers are written to be recallable, not just readable — averaging about 148 characters, which is long enough to carry the reasoning and short enough to say out loud.
A deck like this earns its keep on the second and third pass. Read the syllabus first so you know the shape of the subject, then use the cards to find the specific facts that have not stuck.
Chemistry flashcards FAQ
How many Chemistry flashcards are in this ISC Class 11 deck?
56 cards. This page previews 24 of them, sampled evenly across the deck so you can judge the difficulty before installing anything.
Are these ISC Class 11 flashcards free?
Yes. The preview here is free to read with no signup, and the full 56-card deck is free inside the Examius app.
What do the Chemistry cards cover?
They follow the ISC Class 11 Chemistry syllabus — 5 chapters and 22 topics — so the questions track what is actually examinable.
How should I use these flashcards?
Read the syllabus first so you know the shape of the subject, then drill the deck. Examius schedules each card with spaced repetition, so cards you keep missing come back sooner and ones you know drift further apart.