Grade 10 Chemistry

Periodic Table

Table listing all known elements. The elements are grouped according to their properties and in order of the number of protons in their nucleus.

Periods

Subdivisions of geological time. Periods are the rows of the periodic table.

Groups

Columns of the periodic table containing elements with similar properties.

Periodic Law

Statement made by Mendeleev that the elements with similar properties occur at regular intervals when all elements are listed in order of atomic mass.

Symbols

One (or two) letter code(s) used for elements, often as an abbreviation of their name.

Atomic Numbers

Number of protons in the nucleus of an atom. The atomic number determines which element an atom is.

Relative Atomic Mass

A number that compares the mass of atoms to an agreed mass; such as 112 of the mass of a carbon-12 isotope.

Mass Number

Number or protons and neutrons in the nucleus of an atom.

Alkali Metals

Very reactive metals in group 1 of the periodic table.

Alkaline Earth Metals

Reactive metals in group 2 of the periodic table.

Halogens

Non-metal elements in group 17 of the periodic table.

Noble Gases

Elements in the last column of the periodic table. They are extremely inert.

Transition Metal Block

Block of metallic elements in the middle of the periodic table. (Staircase)

Metals

Elements that conduct heat and electricity; shiny solids which can be made into thin wires and sheets that bend easily. Mercury is the only liquid metal. (Left hand side). Metals lose electrons.

Non-Metals

Elements that do not conduct electricity or heat; they melt and turn into gases easily, and are brittle and often coloured. (upper right hand side). Non-metals gain or share electrons.

Metalloids

Elements that have the appearance of metals but not all the other properties of metals.

Molecules

Particles with two or more atoms joined (bonded) together.

Bohr Diagram

Diagram showing electrons in their shells around the nucleus of an atom.

Shells

Energy levels surrounding the nucleus of an atom into which electrons are arranged.

Electron Configuration

An ordered list of the number of electrons in each electron shell, from inner (low energy) to outer (high energy) shells.

Neutral

Having equal amounts of negative and positive electric charge and, therefore, no overall electric charge. Atoms are neutral whereas ions have either a positive or negative electric charge.

Ions

Atoms or groups of atoms that have lost or gained electrons.

Cations

Atoms or groups of atoms that have lost electrons and are positively charged.

Anions

Atoms or groups of atoms that have gained electrons and are negatively charged.

Ionic Compounds

Compounds containing positive and negative ions held together by the electrostatic force.

Ionic Bond

Attractive force between ions with opposite electrical charge.

Aqueous Solutions

Solutions of ionic compounds in which water is the solvent.

Covalent Compounds (Also Known As Molecular Compounds)

Compounds in which the atoms are held together by covalent bonds.

Lewis Dot Structures

Diagrams using dots to represent the electrons in the outer shell of atoms and to show the bonds between atoms in molecules.

Bonding Electrons

Shared electrons holding two atoms together.

Structural Formula

Diagram showing the arrangement of atoms in a substance with covalent bonds drawn as dashes.

Chemical Formula

Shorthand statement of the elements in a substance showing the relative number of atoms of each kind of element.

Molecular Formula

Shorthand statment of the elements in a molecule showing the relative number of atoms of each kind of element.

Valency

Equal to the number of electrons that each atom needs to gain, lose or share to fill its outer shell.

Electronegativity (not in Sci 10)

a measure of the tendency of an atom to attract a bonding pair of electrons.

Matter

The substance of substances of which any physical object consists or is composed.

Element

A substance of atoms which all have the same number of protons. (Same atomic number)

Compound

A substance formed when two or more chemical elements are chemically bonded together.

Chemical Change

Occurs when a substance combines with another to form a new substance.

Physical Change

Change that does not involve changing the substance's chemical identity. e.g. changing between solid, liquid and gas

Atom

The smallest particle of a chemical element that can exist.

Molecule

A group of atoms bonded together, representing the smallest fundamental unit of a chemical compound.

Proton

A stable subatomic particle occurring in all atomic nuclei, with a positive electric charge equal in magnitude to that of an electron.

Neutron

Subatomic particle of about the same mass as a proton but without an electric charge, present in all atomic nuclei except those of ordinary hydrogen.

Electron

A stable sub-atomic particle with a charge of negative electricity, found in all atoms and acting as the primary carrier of electricity in solids.

Nucleus

The positively charged central core of an atom, consisting of protons and neutrons and containing nearly all of its mass.

Isotope

each of two or more form of the same element that contain equal numbers of protons but different numbers of neutrons.

Reactant

A substance that takes part in and undergoes change during a reaction.

Product

The compound(s) that are formed when a reaction is completed.

Hydrogen Bond

is an attraction between a slightly positive hydrogen atom and a slightly negative atom, often oxygen or nitrogen

intermolecular forces

forces of attraction between molecules

intramolecular forces

bonding forces that hold the atoms of a molecule together

adhesive forces

intermolecular forces that bind a substance to a surface

cohesive forces

intermolecular forces that bind similar molecules to one another

Covalent bonds

Bonds created by sharing electrons with other atoms.

Niels Bohr

1913- discovered that electrons move around the nucleus in orbits called electron shells.

Ernest Rutherford

1909-solar system model of the atom, gold foil experiment- fired negative ions at thin sheet of gold foil, discovered the atomic nucleus and proposed a nuclear model of the atom .

J. J. Thomson

Discovered electrons and suggested Plum pudding model showing atoms composed of electrons

John Dalton

English chemist and physicist who formulated atomic theory that atoms are indivisible and distinct for each element.

Schrodinger (not in Sci 10)

studied energy of electrons and helped develop electron cloud model (orbitals)