Chemistry Unit

Atom

The basic unit in a chemical element.

Proton

A positively charged particle found in the nucleus of an atom.

Neutron

A particle with no charge found in the nucleus of an atom.

Electron

A negatively charged particle that orbits the nucleus of an atom.

Atomic Number (Z)

The number of protons in an atom.

Mass Number (A)

The total mass of protons and neutrons in an atom.

Cation

A positively charged ion formed when an atom loses electrons.

Anion

A negatively charged ion formed when an atom gains electrons.

Molecule

A group of atoms bonded together.

Element

A pure substance made up of one type of atom.

Compound

A substance made of two or more types of atoms bonded together.

Periodic Table

A table that organizes all known elements by their atomic number.

Group

A column in the periodic table, representing elements with similar properties.

Period

A row in the periodic table, representing elements with increasing atomic numbers.

Atomic Radius

The distance from the center of the nucleus to the outermost electron level.

Reactivity

The ability of an element to react with other substances.

Ionization Energy

The amount of energy required to remove an electron from an atom.

Electronegativity

A measure of how strongly an atom attracts shared electrons.

Lewis Dot Diagram

A diagram that shows the number of valence electrons an atom has.

Ionic Bonding

The transfer of electrons between atoms that creates oppositely charged ions.

Covalent Bonding

The sharing of electrons between atoms.

Skeleton Equation

A chemical equation that uses chemical formulas but does not have coefficients.

Chemical Equation

A representation of a chemical reaction using symbols and formulas.

Reactants

Substances that undergo a chemical change in a reaction.

Products

Substances produced as a result of a chemical reaction.

Neutralization Reaction

A reaction between an acid and a base that produces water and salt.

Single Displacement Reaction

A reaction where one element replaces another in a compound.

Double Displacement Reaction

A reaction where two compounds exchange components.

Combustion Reaction

A reaction where a fuel reacts with oxygen, producing energy.

Synthesis Reaction

A reaction where two or more reactants combine to form one product.

Decomposition Reaction

A reaction where a single reactant breaks down into two or more products.

pH Scale

A scale measuring the acidity or basicity of a solution.

Strong Acid

An acid that completely dissociates in water to produce H+ ions.

Weak Acid

An acid that partially dissociates in water.

Arrhenius Acid

A substance that releases hydrogen ions in water.

Arrhenius Base

A substance that releases hydroxide ions in water.

Litmus Test

A method using litmus paper to determine if a solution is acidic or basic.

Universal Indicator

A pH indicator that displays a range of colours in response to pH.

Phenolphthalein

An indicator commonly used in acid-base reactions that changes color.

Polyatomic Ion

An ion made of two or more atoms bonded together.

Monovalent Element

An element that can have only one charge.

Multivalent Element

An element that can have multiple charges.

Crystalline Structure

A solid material whose constituents (atoms, molecules, or ions) are arranged in a highly ordered structure.

Electrolytes

Ionic compounds that dissolve in water to produce ions and conduct electricity.

Diatomic Molecule

A molecule that consists of two atoms, which can be the same or different.

Chemical Change

A change that results in the formation of new chemical substances.

Physical Change

A change that affects one or more physical properties of a substance.

Bohr-Rutherford Diagram

A model that shows the arrangement of electrons around the nucleus of an atom.

Soluble

A substance that can dissolve in water.

Insoluble

A substance that cannot dissolve in water.

Alkali Metals

Elements in Group 1 of the periodic table, known for their reactivity.

Transition Metals

Elements found in Groups 3-12 of the periodic table.

Metalloids

Elements that have properties of both metals and non-metals.

Halogens

Elements in Group 17 of the periodic table, known for their reactivity.

Noble Gases

Inert gases found in Group 18 of the periodic table.

Oxidation

The loss of electrons during a chemical reaction.

Catalyst

A substance that increases the rate of a chemical reaction without being consumed.

Balancing Equations

The practice of ensuring that the number of atoms for each element is the same on both sides of a chemical equation.

Hydrocarbon Combustion

The reaction of hydrocarbons with oxygen to produce carbon dioxide and water.

Law of Conservation of Mass

The principle stating that mass cannot be created or destroyed in a chemical reaction.

Reactants in a Neutralization

An acid and a base that react to form a salt and water.

Acid Base Indicators

Substances that change color in response to the acidity or basicity of a solution.

Covalent Compound

A compound formed by the sharing of electrons between atoms.

Ionic Compound

A compound formed by the electrostatic attraction between oppositely charged ions.

Alkaline Earth Metals

Elements in Group 2 of the periodic table.

Atomic Mass

The weighted average mass of an atom based on its isotopes.

Acid Strength

The degree to which an acid can dissociate into H+ ions when in solution.

Isotope

Atoms of the same element with different numbers of neutrons.

Chemical Reaction Types

Different classifications of reactions such as synthesis, decomposition, and redox.