Acid: A substance with a low pH (less than 7). The lower the pH, the more acidic (due to more H+ ions). Can neutralise bases and form salts.
Alkali metals: Metals in group 1 of the periodic table; they have 1 valence electron. They are highly reactive and form very strongly basic hydroxides.
Base: A substance with a high pH (more than 7). The higher the pH, the more basic (due to more OH- ions). Also known as alkalies, they can neutralise acids and form salts.
Diatomic molecules: Molecules that are comprised of two atoms.
Group: The columns of the periodic table. Elements of the same group have the same number of valence electrons.
Halogens: Elements in the 7th group of the periodic table. They have seven valence electrons, and are all non-metals, whose hydroxides are strongly acidic.
Inert: A substance that does not react. Noble gases are unreactive, therefore they are inert.
Metal: Elements that conduct electricity and heat, and whose hydroxides are basic. They bond together in a giant metallic crystal, with a sea of free electrons.
Noble gas: An element in the last group of the periodic table, group 0 or group 8. It is inert, and has a full outer shell of electrons
Non-metal: Elements that generally do not conduct electricity (carbon is an exception). Form covalent bonds involving a shared pair of electrons, and their hydroxides are acidic.
Period: The rows of the periodic table. Indicates how many shells of electrons there are.
Periodic table: A table of organisation for the chemical elements, developed by Mendeleev (though not quite as we know it today, and there are many other versions)
Valence electrons: Outer-shell electrons
Monday 26 March 2018
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Section 3 a) Specification
3.1 explain the terms homologous series, hydrocarbon, saturated, unsaturated, general formula and isomerism. A homologous series is a grou...
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The group 7 elements, also known as halogens, are F, fluorine, Cl, chlorine, Br, bromine, I, iodine, and At, astatine. They all have antimic...
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Metals can be placed in an order of most to least reactive, called the reactivity series. This can be remembered using an acronym: Plea...
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Particles of a substance can be present in different physical states, the states of matter. They are solid, liquid and gas, and increasing ...
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