C4 Predicting and Identifying Reactions and Products Definitions:
Alkali metals- the elements in Group 1 of the periodic table. They are typically soft and
have relatively low melting points.
Anions- a negatively charged ion. Formed when an atom gains at least one electron.
Catalyst- increases the rate of reaction by providing a different reaction pathway with a
lower activation energy. They are not used up during the reaction.
Cations- a positively charged ion. Formed when an atom loses at least one electron.
Displacement- a chemical reaction in which a more reactive element displaces a less
reactive element from its compound.
Flame test- test used to identify metal ions (cations). Carried out by inserting a
nichrome wire loop with the unknown compound on into a flame and observing the colour.
Halides- the ions formed by halogen atoms when they gain an electron. They have a 1-
charge. E.g. Cl-, Br- and I-.
Halogens- the elements in Group 7 of the periodic table. The halogens gain an electron to
form halide ions with a 1- charge. Down the group the halogens get more reactive and have
higher melting and boiling points.
Instrumental methods- used to detect and identify elements and compounds. They are
accurate, sensitive and rapid.
Noble gases- the elements in Group 0 of the periodic table. They have a stable full outer
shell of electrons which makes them very unreactive.
Transition metal- a metal found between Group 2 and 3 of the periodic table. Typical
properties include high melting points, high densities, form coloured compounds and
catalytic activity.
Alkali metals- the elements in Group 1 of the periodic table. They are typically soft and
have relatively low melting points.
Anions- a negatively charged ion. Formed when an atom gains at least one electron.
Catalyst- increases the rate of reaction by providing a different reaction pathway with a
lower activation energy. They are not used up during the reaction.
Cations- a positively charged ion. Formed when an atom loses at least one electron.
Displacement- a chemical reaction in which a more reactive element displaces a less
reactive element from its compound.
Flame test- test used to identify metal ions (cations). Carried out by inserting a
nichrome wire loop with the unknown compound on into a flame and observing the colour.
Halides- the ions formed by halogen atoms when they gain an electron. They have a 1-
charge. E.g. Cl-, Br- and I-.
Halogens- the elements in Group 7 of the periodic table. The halogens gain an electron to
form halide ions with a 1- charge. Down the group the halogens get more reactive and have
higher melting and boiling points.
Instrumental methods- used to detect and identify elements and compounds. They are
accurate, sensitive and rapid.
Noble gases- the elements in Group 0 of the periodic table. They have a stable full outer
shell of electrons which makes them very unreactive.
Transition metal- a metal found between Group 2 and 3 of the periodic table. Typical
properties include high melting points, high densities, form coloured compounds and
catalytic activity.
