Chemistry - Chemistry Definitions Flashcards
Homogeneous mixtures
Same consistency all the way through
Mixtures
Substances that are physically combined. Are impure
Heterogeneous mixtures
Different consistency all the ways through
E.g. Marbles and sand
Pure substances
A single substance containing no other substances
Elements
Simplest pure substance that can’t be broken down. About 90 occur naturally
Compounds
Two or more elements chemically combined
Atoms
Make up all substancesi. Small particles
Metalloids/Semi-metals
Not metals or non-metals. Resistance decreases as the temperature increases.
Kinetic Molecular Theory
Explains the motion behavior of solids, liquids and gases
Brownian Motion
Random motion of particles
Temperature
Degree of hotness/coldness. Measure of internal energy of particles measured in Celsius.
Heat
Transit of energy due to temperature difference
Electron configuration
Arrangement of electrons
Quantized
Electron contains a certain amount of energy
Valence electrons
Outer electrons on the last energy level
Core electrons
Rest of electrons in atoms
Intermolecular forces
Hold solids and liquids together
Octet rule
Electrons generally try get an outer ring of eight electrons
Chemical bonding
Interactions between matter creating substances with new physical/chemical properties.
Electronegativity
A number rating how strongly the atom pulls the bonded electrons to itself
Ion
Small charged particle which has lost/gained electrons
Valency
Number of valence electrons
Anions
Negatively charged ions
Cations
Positively charged electrons
Stock notation
Roman numerals used to show valency of transition metals (e.g. iron II)
Electron affinity
Amount of energy released per mole when an atom gains an electron
Atomic Mass Unit (1 a.m.u.)
One twelfth of the mass of a carbon-12 atom.
1 a.m.u. = 1.66 x 10^-27 kg
Elemental unit of charge (e)
Smallest unit of electronic change
Electron : -1.6 x 10^-19 C
Proton : 1.6 x 10^-19 C
