S3 Junior Science - Atoms, Elements, Compounds, and Mixtures

Flashcards covering atoms, elements, the periodic table, chemical bonding, compounds, mixtures, and the extraction of metals.

Atom

The smallest part of an element

Elements

Substances that contain only one kind of atom.

Molecule

A group of atoms represented by a chemical formula indicating the number of atoms it contains.

Classification of elements

Elements classified into metals, non-metals, and semi-metals.

Malleable Substance

A substance that can be bent or pressed into different shapes.

Brittle Substance

A substance that can be broken into tiny pieces easily.

Ductile Substance

A substance that can be pulled into a thin wire.

Nucleus

The center of an atom that has most of its mass.

Atomic Number

The number of protons in an atom.

Mass Number

The total number of protons and neutrons in an atom.

Ion

A particle carrying an electrical charge.

Positive Ion

A positive ion formed by losing electrons; also known as a cation.

Negative Ion

A negative ion formed by gaining electrons; also known as an anion.

Periodic Table

How the periodic table organizes elements in a systematic order based on increasing atomic number.

Groups

Vertical columns in the periodic table; elements in the same _ have similar chemical properties.

Periods

Horizontal rows in the periodic table.

Period (Electronic Arrangement)

The number of electron shells occupied by an atom.

Group (Electronic Arrangement)

The number of electrons in the outermost shell (valent shell) of an atom.

Stable Atoms

Atoms are stable (unreactive) if their outermost shell is fully occupied, like those of Group VIII/0 (noble gases).

Formation of Ions

Atoms other than noble gases are usually not stable and bond to other atoms to gain the same arrangement of outer-shell electrons as a noble gas.

Monoatomic Ion

Simple ions derived from a single atom.

Polyatomic Ion

Ions derived from a group of atoms.

Ionic Bond

The strong electrostatic attraction between positive and negative ions.

Ionic Bond Formation

Formed by the transfer of one or more electrons from one atom (or group of atoms) to another, usually between a metal and a non-metal.

Element Definition

A substance that contains only one kind of atom and cannot be broken down into anything simpler by chemical methods. Pure substance.

Compound Definition

A pure substance that contains two or more elements chemically bonded together and can be broken down into its constituent elements by chemical methods. Pure substance.

Mixture Definition

Composed of two or more substances (elements or compounds) that are NOT chemically bonded together and can be separated by physical methods. No formation of new substances.

Sharp Melting and Boiling Points

Melting points and boiling points remain constant.

Range of Melting and Boiling Points

melting points and boiling points occur over a range of temperature

H2O

Water

Water Elements

Hydrogen and Oxygen

NaCl

Salt

Sodium and Chloride

Salt Elements

Chemical Equation

A statement, in formulae, showing the relative numbers of particles involved in a chemical reaction.

Balancing Chemical Equations

Having the same number of each type of particle on both sides of the equation, as particles cannot be destroyed or created.

Electrolysis

Using electricity to assist in the decomposition of a compound.

Example of Reduction

Heating with Carbon

Metal Reactivity

Reactive metals form stronger bonds with other elements.

Metal Extraction

The higher the position of a metal in the reactivity series, the more difficult its extraction from its ore is.

Oxidation

Gaining oxygen atoms

Reduction

Losing oxygen atoms

Electrolyte

A molten compound that conducts electrity

Cryolite Uses

Aluminium dissolved in molten cryolite decreases the melting point

Crude Oil

Thick, black liquid with a pungent odor comprised of hydrogen and carbon atoms only.

Length of Hydrocarbon

The length of the molecule

Fractional Distillation

Process to separate crude oil into fractions of different boiling points without air.

Fraction (Crude Oil)

A mixture of hydrocarbons with similar boiling points.