SNC 1W Unit: Chemistry – The Nature of Matter

Comprehensive vocabulary flashcards covering particle theory, physical and chemical properties, characteristic properties, periodic table patterns, atomic models, and chemical bonding from the Grade 9 SNC 1W Chemistry unit.

Particle Theory of Matter

A scientific theory explaining the composition and behavior of matter: all matter is made of tiny particles, all particles of a pure substance are identical, particles have empty spaces between them, particles are in constant motion, temperature increases particle speed, and particles exert attractive forces on one another.

Pure Substance

A type of matter that consists of only one kind of particle and exhibits constant, uniform physical and chemical properties throughout.

Mixture

A combination of two or more different pure substances that are physically combined and retain their individual properties without chemically reacting.

Mechanical Mixture

A heterogeneous mixture in which two or more different substances remain visually distinct and can be identified separately (such as pizza or chocolate chip ice cream).

Solution

A homogeneous mixture of two or more substances that appears uniform throughout because the individual components are mixed at the particle level (such as clear apple juice).

Alloy

A solid solution composed of two or more metals, or a metal combined with non-metals, engineered to enhance properties such as strength or corrosion resistance.

Qualitative Property

A descriptive characteristic of a substance that can be observed using the senses without numeric measurement, such as colour, texture, odour, or metallic lustre.

Quantitative Property

A characteristic of a substance that is measured and expressed with a numerical value and specific units, such as length, mass, volume, or boiling point.

Physical Property

A characteristic of a substance that can be observed or measured without altering the chemical identity or composition of the substance.

Chemical Property

A characteristic of a substance that describes its ability to undergo a chemical reaction and transform into one or more new substances.

Physical Change

A change in the size, shape, or state of matter of a substance in which no new substance is formed and the chemical identity remains unaltered.

Chemical Change

A process in which one or more substances interact to form one or more entirely new substances with distinct chemical and physical properties.

Characteristic Physical Property

A physical property unique to a substance that does not depend on the size or shape of the sample and can be used to identify an unknown substance (such as density or boiling point).

Density

A characteristic physical property defined as the ratio of mass per unit volume of a substance, expressed mathematically as $D = \frac{m}{V}$ in units such as $\text{g/cm}^3$ or $\text{g/mL}$.

Element

A pure substance that cannot be broken down into simpler chemical substances by any physical or chemical means, consisting of only one type of atom.

Compound

A pure substance composed of two or more different elements chemically bonded together in fixed, definite proportions.

Staircase Line

The bold, stepped diagonal line on the periodic table that demarcates metallic elements on the left from non-metallic elements on the right, bordered by metalloids.

Metal

An element that is typically shiny, malleable, ductile, and an effective conductor of electricity and heat, situated to the left of the staircase line on the periodic table.

Non-metal

An element that is generally a poor conductor of heat and electricity, brittle when solid, and located to the right of the staircase line on the periodic table.

Period

A horizontal row of elements on the periodic table whose atoms all possess the same number of electron orbits (energy shells).

Group (Family)

A vertical column of elements on the periodic table containing elements that share similar chemical and physical properties because they have the same number of valence electrons.

Alkali Metals

The chemical family of soft, highly reactive elements located in Group 1 of the periodic table (excluding hydrogen) that possess one valence electron.

Alkaline Earth Metals

The chemical family of shiny, reactive metals located in Group 2 of the periodic table that possess two valence electrons.

Halogens

The chemical family of highly reactive non-metals located in Group 17 of the periodic table that have seven valence electrons.

Noble Gases

The chemical family of unreactive, stable gases located in Group 18 of the periodic table that have full outermost electron orbits.

Atom

The smallest unit of an element that maintains the chemical identity and properties of that element, composed of protons, neutrons, and electrons.

Electron

A subatomic particle discovered by J. J. Thomson that possesses a negative electrical charge ($-1$) and resides in orbits surrounding the atomic nucleus.

Proton

A subatomic particle located in the atomic nucleus that possesses a positive electrical charge ($+1$) and determines the atomic number of an element.

Neutron

An electrically neutral subatomic particle located within the nucleus of an atom, discovered by James Chadwick.

Atomic Number

The total number of protons located in the nucleus of an atom, which uniquely determines the identity of an element.

Mass Number

The total integer sum of protons and neutrons located in the nucleus of an individual atom.

Isotopes

Atoms of the same element that have identical numbers of protons but differing numbers of neutrons, resulting in different mass numbers.

Bohr–Rutherford Diagram

A diagrammatic model of an atom displaying the numbers of protons and neutrons in the central nucleus surrounded by concentric circular orbits containing electrons.

Molecule

A distinct chemical entity formed when two or more atoms bond together via covalent electron sharing.

Diatomic Molecule

A molecule composed of exactly two atoms of the same or different elements chemically bonded together (e.g., $H_2$, $N_2$, $O_2$, $F_2$, $Cl_2$, $Br_2$, $I_2$).

Hydrocarbon

A class of chemical compounds composed solely of hydrogen and carbon atoms, such as propane ($C_3H_8$) or octane ($C_8H_{18}$).

Ion

A charged entity formed when an atom or group of bonded atoms gains or loses one or more valence electrons.

Ionic Compound

A chemical compound composed of positive ions (cations) and negative ions (anions) held together by strong electrostatic attractive forces in a crystal lattice.

Covalent Bond

A chemical bond formed when two non-metallic atoms share one or more pairs of valence electrons to attain stable, filled outer electron shells.