The particulate nature of matter means that…
All matter is made up of particles (matter is particulate).
Matter
Something that has mass and occupies space. Can be classified as pure substance or mixture.
Types of matter
Elements, compounds, mixtures.
Elements and compounds are pure substances.
Elements
Primary constituents of matter, which cannot be further broken down chemically (by chemical methods). Elements are fundamental components and have one type of atom
Compounds
Consists of more than one type of atom (atoms of different elements) chemically bonded together in a fixed ratio. The property of a compound is different from its constituent elements.
Mixtures
Contain more than one element and/or compound in no fixed ratio. Not chemically bonded and so can be separated by physical methods. Retains the properties of its components.
Mixture can be classified as…
homogeneous or heterogeneous
Homogeneous mixture
Mixture with uniform and definite composition
Heterogeneous mixture
Mixture with non-uniform composition
Sublimation
solid to gas
Deposition
Gas to solid
Condensation
Gas to liquid
Gas to plasma
Ionisation
Plasma to gas
De-ionisation
Celsius to Kelvin
Celsius + 273.15K
Nuclear symbol notation
Upper number is mass number (A)
Lower number is atomic number (Z)
Chemical symbol for the element in the middle
Isotopes
Atoms of the same element with different numbers of neutrons.
Same chemical properties, different physical properties.
Why do isotopes have the same chemical properties?
Because chemical behaviour is determined by the number of electrons and isotopes have the same number of electrons, and neutrons don’t take part in electronic configuration.
Why do isotopes have different physical properties?
Because they have a different mass since they have different numbers of neutrons. Physical properties are dependent on atomic mass.
Heavier isotopes have lower zero-point energy, so more energy is required to break the bonds and dissociate the molecules.
Relative atomic mass
the ratio of the average mass of atoms of an element to 1/12th of the mass of an atom of Carbon-12.
The RAM depends on…
the abundance of different isotopes in nature.
RAM formula
sum(mass x abundance)/total abundance
Mass spectrometer
An analytical device used to determine the abundance of various isotopes of an element based on a measurement of the m/z ratio of ions within a sample of the element.
mass-to-charge (m/z) ratio
The ratio of the mass of an ion divided by its charge.