Science Exam Year 8 Term 4- Earth and Space

Element

A substance made up of only one type of atom, which cannot be broken down into another substance by chemical or physical change.

Molecule

A small group of atoms joined together by chemical bonds, which can be the same or different types of atoms.

Lattice

A continuous framework in which atoms are all joined together and rigid, forming solids.

Properties of Elements

Unique characteristics of each element, including state of matter, colour, reflectance, conductivity, melting point, atomic number, type (metal, non-metal, metalloid), and atomic weight.

Periodic Table

An arrangement of elements in order of atomic number; similar properties are arranged in the same column.

Chemical Formula

A symbol that shows the chemical composition of a substance; for example, oxygen is represented as O2.

Compound

A substance formed when two or more different elements are chemically bonded together, having different properties from the individual elements.

Mixture

A combination of substances that can be physically separated, where particles are not joined by chemical bonds.

Physical Change

A change affecting a substance's physical properties without changing its chemical identity; the same substance remains before and after the change.

Chemical Change

A process in which one or more new substances are formed, often indicated by signs such as color change, temperature change, production of light or sound, or formation of gas.

Reactants

The substances that undergo a reaction in a chemical change.

Products

The new substances formed from a chemical reaction.

Independent Variable

The variable that is changed in an experiment.

Dependent Variable

The variable that is measured in response to changes in the independent variable.

Controlled Variable

The factors that are kept constant throughout an experiment.

Qualitative Data

Data expressed in words and explanations.

Quantitative Data

Data expressed in numbers and measurable amounts.

Continuous Data

Data that includes decimals and can take on any value.

Discrete Data

Data that can only take on specific, separate values.

Graph

A visual representation of data, which includes axes, a title, units, correct increments, and different types such as column, line, and scatter plot.