definitions Flashcards
atom
The smallest unit of a substance that can exist
nucleus
The central part of an atom containing the protons and neutrons
proton
A positive particle within the nucleus of an atom
neutron
A neutral particle within the nucleus of an atom
electron
A very tiny negative particle that exists in shells around the nucleus of an atom
atomic number
The number of positive protons in the nucleus of an atom
mass number
The total number of protons and neutrons within the nucleus of an atom
Bohr model
A model of an atom showing a small nucleus (positively charged) surrounded by negative electrons moving around the nucleus in orbits.
periodic table
A table of the chemical elements arranged in order of atomic number so that elements with similar atomic structure appear in vertical columns.
period
a horizontal row in the periodic table
group
a vertical row in the periodic table
electron shell
Regions around a nucleus that contain a specific number of electrons
electron configuration
The specific arrangement of electrons in shells around the nucleus
valance electron
Electrons in the outermost shell of an atom
ion
An atom that has lost electrons or gained electrons and is no longer neutral
polyatomic ion
Ions that contain more than one type of atom
transition metal
The elements in the middle section of the periodic table. Transition metal ions can exhibit more than one charge
compound
Two or more elements joined together through a chemical bond
element
Consists of ONLY one type of atom
ionic compound
The attraction between a positive ion and a negative ion
covalent compound
Two or more elements bonded together through the sharing of electron pairs
reactant
The starting substances in a chemical reaction
product
The finishing substances in a chemical reaction
chemical reaction
The re arrangement of atoms to form new substances
combustion
A chemical reaction where a substance is combined with oxygen and energy is released
synthesis reaction
A reaction where simple elements or compounds combine to form a more complex compound
decomposition reaction
A reaction where a more complex compound splits into simpler elements or compounds
displacement reaction
A reaction where a more reactive element “pushes out” a less reactive elements from a compound and takes its place
pop test
A test for hydrogen gas, a popping sound is heard when the gas is hydrogen
limewater
A test for carbon dioxide gas, colourless limewater turns cloudy when the gas is carbon dioxide
splint test
A test for oxygen gas, the splint glows brightly when the gas is oxygen
soluble
A substance that dissolves in water forming a transparent solution
insoluble
A substance that does not dissolve in water
precipitation reaction
A reaction between two transparent solution where one of the products is not soluble in water
endothermic
A reaction that released energy to the surroundings
exothermic
A reaction that absorbs energy from the surroundings
