S4 All Definitions Flashcards
Element
A pure substance that cannot be broken down into anything simpler by chemical methods.
Compound
A pure substance that consists of two or more elements chemically joined together.
Mixture
It is made up of two or more substances (elements or compounds) that are not chemically joined together.
Solute, solvent, solution
Solute + solvent = solution
Dilute solution
It contains a small amount of solute in a given volume of solution.
Concentrated solution
It contains a large amount of solute in a given volume of solution.
Saturated solution
It contains solute such that no more solute dissolved in the solution at the temperature.
Filtrate
Substances that pass through the filter paper in filtration.
Residue
Substances that are trapped on the filter paper in filtration.
Distillate
Liquid product condensed from vapour in distillation.
Physical change
A change in which no new substance is formed.
Chemical change
A change in which at least one new substance is formed.
Physical properties
Properties that can be observed or measured without changing the chemical composition of the substance.
Chemical properties
Properties that can be observed or measured without changing the chemical composition of the substance only when the substance undergoes a chemical change to form new substances.
Ores
Rocks containing minerals in concentrations that are high enough for economical extraction.
Effervescence
Bubbling / fizzing
Weathering
The process where rock is dissolved, worn away or broken down into smaller and smaller pieces.
Erosion
The process of moving weathered rock materials to another place by ice, water, wind, or gravity.
Atom
The smallest particle of an element that still has its chemical properties.
Brittle
Appears hard on the surface but breaks easily.
Malleable
Can be hammered into a shape
Ductile
Can be drawn into a wire
Metalloids
Elements that do not fit easily into metals or non-metals.
Semi-conductor
Pure form does not conduct electricity, conductivity increases when impurity is added.
Z
Atomic number
Atomic number (Z)
Number of protons in an element.
A
Mass number
Mass number (A)
Sum of numbers of protons and neutrons of an atom.
Isotopes
Difference atoms of an element which have the same number of protons but a different number of neutrons.
Relative isotopic mass
Mass of an isotope of an element, relative to 1/12 the mass of a carbon-12 atom.
Relative atomic mass
Weighted mean mass of an element taking in to account the relative abundance of isotopes in a naturally occurring sample of the element, relative to 1/12 the mass of a carbon-12 atom.
Transition metals
Metals between group II and group III of the periodic table.
Period number
Indicates the number of occupied electron shells on an atom of the element.
Group number
Indicates the number of outermost shell electrons in an atom of the element.
Alkali metals
Elements in group I
Alkaline earth metals
Elements in group II
Halogens
Elements in group VII
Noble gases
Elements in group 0
Chemically inert
Rarely react with other substances
Monoatomic ion
Formed when one atom loses or gains one or more electrons.
Cation
Positive ion
Anion
Negative ion
Cation (+)
Formed when an atom of a metal (/ hydrogen) loses one or more outermost shell electrons.
Anion (-)
Formed when an atom of a non-metal gains one or more outermost shell electrons.
Charge of monoatomic cation
Group number of the element
Charge of monoatomic anion
8 - group number of the element
Conductors
Substances which conduct electricity but are not chemically changed during electrical conduction.
Electrolytes
Substances which conduct electricity in molten state or aqueous solution but not in solid state, and are decomposed during the conduction.
Non-conductors
Substances that do not conduct electricity in solid, molten state, or aqueous solution.
Ionic bond
The strong electrostatic forces of attraction between oppositely charged ions.
Ionic bond formation
Electrons are transferred from one atom (a group of atoms) to another (or group of atoms).
Oxoanion
Polyatomic anion with oxygen
Polyatomic ions
Ione formed from a group of atoms
Chemical formula
A way to represent a chemical substance by using symbols and numbers.
Delocalised electrons
Outermost shell electrons of atoms of metals that become free and move randomly throughout the metal.
Metallic bond
The strong electrostatic forces of attraction between positive metal ions and a “sea” of delocalised electrons.
