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🇮🇳 ICSE Class 9 · flashcards
ICSE Class 9 Chemistry Flashcards
51 question-and-answer cards covering Chemistry as it is examined in ICSE Class 9. 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.
How do you calculate the number of neutrons in an atom?
Number of neutrons = Mass number (A) − Atomic number (Z).
What is the maximum number of electrons a shell can hold according to the 2n^2 rule?
2n^2, where n is the shell number: K=2, L=8, M=18, N=32.
What is the maximum number of electrons that the outermost shell can hold?
8 electrons (the octet rule); the valence shell cannot hold more than 8.
What are valence electrons?
The electrons present in the outermost shell of an atom; they determine the atom's valency and chemical behaviour.
What are isotopes?
Atoms of the same element having the same atomic number but different mass numbers (different number of neutrons), e.g. hydrogen-1, deuterium, tritium.
What are isobars?
Atoms of different elements having the same mass number but different atomic numbers, e.g. Ar-40 and Ca-40.
Write the electronic configuration of magnesium (Z = 12).
2, 8, 2 (K=2, L=8, M=2).
What is valency?
The combining capacity of an element, i.e. the number of electrons an atom loses, gains, or shares to achieve a stable (octet) configuration.
What is a symbol in chemistry?
A short abbreviation used to represent one atom of an element, e.g. H for hydrogen, Na for sodium (from Latin natrium).
What is the chemical formula of a substance?
A representation of a molecule using symbols and subscripts showing the kinds and numbers of atoms present, e.g. H2O.
What is a radical (ion)?
An atom or group of atoms carrying a net positive or negative charge that acts as a single unit in reactions, e.g. SO4^2-, NH4^+.
State the valencies of the radicals sulphate, nitrate, and carbonate.
Sulphate (SO4) = 2, nitrate (NO3) = 1, carbonate (CO3) = 2.
Write the chemical formulas of: calcium oxide, sodium chloride, and carbon dioxide.
Calcium oxide = CaO; sodium chloride = NaCl; carbon dioxide = CO2.
Write the chemical formula of calcium hydroxide and ammonium sulphate.
Calcium hydroxide = Ca(OH)2; ammonium sulphate = (NH4)2SO4.
What is a chemical equation?
A symbolic representation of a chemical reaction using formulas of reactants and products separated by an arrow.
Why must a chemical equation be balanced?
To obey the law of conservation of mass: the number of atoms of each element must be equal on both sides of the equation.
What do the symbols (s), (l), (g), and (aq) indicate in an equation?
Solid, liquid, gas, and aqueous (dissolved in water) states of the substances.
What is a physical change?
A temporary, usually reversible change in which no new substance is formed and only physical properties (state, shape, size) change, e.g. melting of ice.
What is a chemical change?
A permanent, usually irreversible change in which one or more new substances with new properties are formed, e.g. burning of paper or rusting of iron.
Give three observable signs that a chemical change has occurred.
Change in colour, evolution of a gas, formation of a precipitate, or a change in temperature/energy (heat or light).
State two key differences between physical and chemical changes.
Physical change: no new substance formed, easily reversible. Chemical change: new substance(s) formed, generally irreversible and accompanied by an energy change.
Is the burning of a candle a physical change, a chemical change, or both? Explain.
Both: the melting of wax is a physical change, while the burning of the wax vapour (combustion) is a chemical change.
What chemical change occurs in iron exposed to moist air, and what is the product?
Rusting, in which iron reacts with oxygen and water to form hydrated iron(III) oxide (rust), Fe2O3·xH2O.
Is dissolving sugar in water a physical or chemical change, and why?
A physical change, because no new substance is formed and the sugar can be recovered by evaporating the water.
What this deck covers
The Chemistry deck follows the ICSE Class 9 Chemistry syllabus — 1 chapters and 5 topics — so questions land on material that is genuinely examinable rather than trivia around it. That works out to roughly 51.0 cards per chapter.
Answers are written to be recallable, not just readable — averaging about 104 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 ICSE Class 9 deck?
51 cards. This page previews 24 of them, sampled evenly across the deck so you can judge the difficulty before installing anything.
Are these ICSE Class 9 flashcards free?
Yes. The preview here is free to read with no signup, and the full 51-card deck is free inside the Examius app.
What do the Chemistry cards cover?
They follow the ICSE Class 9 Chemistry syllabus — 1 chapters and 5 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.