Cambridge Science 9/10: Chemical Reactions and Atomic Structure

Comprehensive vocabulary flashcards covering atomic structure, isotopes, ions, bonding, and chemical reaction principles based on the Cambridge Science Year 10 curriculum.

Protons

Subatomic particles with a $+$ charge found in the nucleus that determine the type of atom.

Neutrons

Subatomic particles with no charge found in the nucleus that, along with protons, determine the mass and stability of an atom.

Electrons

Very light subatomic particles with a $-$ charge that orbit the nucleus.

Atomic number

The number of protons in an atom, which identifies the element.

Mass number

The total number of protons and neutrons in an atom.

Isotopes

Atoms of the same element that have the same number of protons but a different number of neutrons.

Ion

An atom that is not neutral because the number of protons and electrons are not equal.

Cations

Positive ions formed when an atom loses electrons, usually metals with fewer than $4$ valence electrons.

Anions

Negative ions formed when an atom gains electrons, usually non-metals with more than $4$ valence electrons.

Polyatomic ions

Ions that are made up of multiple atoms, such as Hydroxide $(OH^-)$ or Sulfate $(SO_4^{2-})$.

Electronic configuration

The arrangement of electrons in shells, where the first four shells can hold a maximum of $2$, $8$, $8$, and $32$ electrons respectively.

Chemical reaction

A process during which atoms are rearranged to make new substances.

Reactants

The substances that undergo change in a chemical reaction, placed on the left-hand side of the chemical equation arrow.

Products

The substances formed in a chemical reaction, placed on the right-hand side of the chemical equation arrow.

Effervescence

Rapid bubbling or gas being produced, which serves as evidence of a chemical change.

Law of Conservation of Mass

The principle stating that matter can neither be created nor destroyed in chemical reactions; the mass of reactants must equal the mass of products.

Coefficients

Numbers placed in front of chemical symbols in an equation to balance the number of atoms on each side.

Native metals

Non-reactive metals, such as gold, silver, and copper, that are found naturally in their elemental form.

Ores

Natural compounds, typically containing reactive metals, from which pure metals can be extracted.

Electrolysis

An expensive industrial process that involves passing an electric current through a molten form of impure metal to extract reactive metals like sodium and potassium.

Green chemistry

A framework of $12$ principles used to help manufacturers produce products more sustainably and reduce energy and greenhouse gas production.

Monatomic

A substance existing as a single atom.

Diatomic

Two atoms bonded together.

Exothermic reactions

Chemical reactions that release energy to the surroundings, such as fire burning wood.

Endothermic reactions

Chemical reactions that take in energy from the surroundings, such as photosynthesis.

Synthesis

A type of chemical reaction where two or more reactants combine to form one new substance.

Decomposition

A type of chemical reaction where one single reactant breaks up into multiple products.

Displacement

A type of reaction where elements are exchanged between two reactants.

Neutralisation

A reaction where an acid and a base are mixed to produce a salt and water.

Precipitation

A reaction where two solutions are mixed and a solid substance forms.

Reaction rate

The quantity of reactant used up or product made per unit time, usually measured in $g/s$ or $ml/s$.

Activation energy

The minimum energy required for a successful collision between particles to start a chemical reaction.

Catalyst

A substance like amylase that increases the reaction rate by decreasing the activation energy without being used up.

Mole ($n$)

A unit of measurement where one mole contains $6.022 \times 10^{23}$ elementary entities.

Avogadro constant ($N_A$)

The number of elementary entities in a mole, defined as $6.022 \times 10^{23} \, mol^{-1}$.

Molar mass ($M$)

The mass of a substance per mole, often expressed in the units $g \, mol^{-1}$.