Year 10 Chemistry: Chemical Patterns and Chemical Reactions

Comprehensive vocabulary flashcards covering atomic structure, periodic trends, ionic and covalent bonding, formula calculations, chemical reaction classifications, safety guidelines, collision theory, and reaction rates for Year 10 Chemistry.

Atom

The smallest whole particle that makes up matter, having a diameter of approximately $1 \times 10^{-8}\,\text{cm}$.

Element

A pure substance that contains only one kind of atom.

Compound

A chemical substance composed of two or more different kinds of atoms bonded together.

Proton

A positively charged subatomic particle ($+1$ charge) located within the atomic nucleus with a relative mass of $1\,\text{a.m.u.}$.

Neutron

An uncharged subatomic particle ($0$ charge) located inside the atomic nucleus with a relative mass of $1\,\text{a.m.u.}$.

Electron

A rapidly moving, negatively charged subatomic particle ($-1$ charge) located around the nucleus with a relative mass of $0\,\text{a.m.u.}$.

Atomic Number

The total number of protons in an atom's nucleus, which uniquely defines each element on the periodic table.

Mass Number

The total number of protons and neutrons combined in the nucleus of an atom.

Isotopes

Atoms of the same element that contain identical numbers of protons but different numbers of neutrons.

Atomic Mass

The weighted average mass of all naturally occurring isotopes of an element, based on their isotopic mass and natural abundance.

Periodic Table

A systematic tabular display of all 118 known elements arranged in order of increasing atomic number, displaying recurring chemical and physical patterns.

Period

A horizontal row in the periodic table (numbered 1 through 7) corresponding to the number of electron shells an atom possesses.

Group

A vertical column in the periodic table (numbered 1 through 18) containing elements that possess identical numbers of valence electrons and similar chemical properties.

Malleability

The physical property of a metal allowing it to be bent or hammered into flat sheets and varying shapes without breaking.

Ductility

The physical property of a metal allowing it to be drawn or stretched into thin wires.

Metalloids

A set of eight elements (boron, silicon, arsenic, germanium, antimony, polonium, astatine, and tellurium) that display intermediate physical and chemical properties of both metals and non-metals.

Valence Electrons

Electrons residing in the outermost electron shell of an atom that participate in chemical bonding and chemical reactions.

Octet Rule

The chemical rule stating that atoms gain, lose, or share electrons to achieve a stable arrangement of eight electrons in their outermost shell.

Electron Subshell

Energy subdivisions within electron shells designated as $s$, $p$, $d$, and $f$, holding maximum capacities of $2$, $6$, $10$, and $14$ electrons respectively.

Atomic Orbital

A defined region within a subshell representing the final location of electrons, capable of accommodating a maximum of $2$ electrons.

Atomic Radius

The distance from the center of the nucleus to the outer boundary of the electron cloud, which decreases across a period and increases down a group.

Electronegativity

A measure of how strongly an atom attracts shared bonding electrons toward itself in a chemical bond.

Cation

A positively charged ion formed when a metal atom with low electronegativity loses one or more valence electrons.

Anion

A negatively charged ion formed when a non-metal atom with high electronegativity gains one or more electrons.

Ionic Bonding

A type of chemical bonding resulting from the electrostatic attraction between oppositely charged cations and anions after electron transfer.

Ionic Lattice

A regular, repeating three-dimensional array of alternating cations and anions held together by multidirectional electrostatic attractions.

Covalent Bond

A chemical bond formed between non-metal atoms through the sharing of pairs of electrons.

Bonding Pair

A pair of shared valence electrons that holds two atoms together in a covalent bond.

Lone Pair

A pair of valence electrons in a molecule that is not shared with another atom.

Metal Reactivity

The ease with which a metal atom loses its valence electrons to form positive cations.

Reactivity Series of Metals

A ranked progression of metals arranged in descending order of chemical reactivity, where elements higher up lose electrons more readily and can displace metals or hydrogen below them.

Valency

The combining power of an element, equivalent to the number of electrons each atom must gain, lose, or share to attain an outer shell of eight electrons.

Polyatomic Ion

A tightly bound group of atoms that behaves as a single unit and possesses a net positive or negative electrical charge (e.g., $\text{NO}_3^{-}$, $\text{SO}_4^{2-}$, $\text{OH}^{-}$, $\text{CO}_3^{2-}$, $\text{PO}_4^{3-}$).

Formula Mass

The sum of the atomic masses of all atoms present in the empirical or chemical formula of a substance, expressed in atomic mass units ($\text{a.m.u.}$).

Percent Composition

The percentage by mass of each element in a chemical compound, determined using the formula: $\frac{\text{grams of element}}{\text{grams of compound}} \times 100$.

Law of Conservation of Mass

A fundamental scientific law stating that the total mass in a closed system remains constant during a chemical reaction, as atoms are neither created nor destroyed.

Dangerous Goods

Chemical substances categorized into nine hazard classes based on their greatest immediate physical danger to people, property, or the environment.

Hazardous Substances

Chemical agents classified according to their capacity to cause acute or chronic harm directly to human health (e.g., corrosives, toxic agents, irritants).

Safety Data Sheet (SDS)

A formal document supplying complete information regarding a chemical's ingredients, hazards, storage, safe handling, and first-aid instructions.

Synthesis Reaction

A chemical reaction in which two or more simple reactants combine to generate a single new product, following the general equation $A + B \rightarrow AB$.

Decomposition Reaction

A chemical reaction in which a single compound breaks down into two or more simpler chemical species ($AB \rightarrow A + B$), typically requiring energy input (endothermic).

Single Displacement Reaction

A chemical reaction where a more reactive element replaces a less reactive element within a chemical compound ($A + BC \rightarrow AC + B$).

Double Displacement Reaction

A chemical reaction in which the cations and anions of two reacting ionic compounds exchange partners ($AB + CD \rightarrow AD + CB$).

Precipitate

An insoluble solid that forms and settles out of an aqueous solution during a chemical reaction.

SNAP Rule

A solubility mnemonic stating that all ionic compounds containing Sodium ($\text{Na}^+$), Nitrate ($\text{NO}_3^{-}$), Ammonium ($\text{NH}_4^+$), or Potassium ($\text{K}^+$) ions are soluble in water and never form precipitates.

Neutralisation Reaction

A specific double displacement reaction occurring between an acid and a base that produces a neutral salt and water.

Rate of Reaction

The speed at which reactants are consumed or products are produced in a chemical reaction over a given unit of time.

Collision Theory

The kinetic model stating that chemical reactions require reactant particles to collide with sufficient energy (activation energy) and in the correct geometric orientation.

Activation Energy ($E_a$)

The minimum threshold of kinetic energy required by colliding reactant particles to break existing bonds and initiate a chemical reaction.

Catalyst

A substance that speeds up a chemical reaction by providing an alternative reaction pathway with a lower activation energy, remaining chemically unchanged at the end.

Enzyme

A specialized, naturally occurring biological protein catalyst that regulates and accelerates biochemical reactions in living organisms.

Mass Loss Method

An experimental technique for tracking reaction rates involving gaseous products by recording the decrease in total flask mass over time using an electric balance.

Inverted Cylinder Method

An experimental technique for measuring the rate of gas production by collecting gas via downward displacement of water inside an inverted graduated cylinder.