Studied by 13 peopleAtom
The simplest part of an element that can exist and take part in chemical reactions.
Element
A pure substance which contains only one type of atom. It cannot be split into anything simpler by a chemical reaction.
Compound
A pure substance which contains two or more different elements chemically joined.
Mixture
A substance that contains two or more different elements not chemically joined and can be separated easily.
Atomic Number
The number of protons present in an atom.
Mass Number
The total number of protons and neutrons in an atom.
Isotopes
Atoms of the same element which have the same number of protons but a different number of neutrons.
Ion
A charged particle formed when an atom either loses or gains electrons.
Ionic Bond
The attraction between oppositely charged ions, forming large regular lattice structures.
Covalent Bond
The sharing of electron pairs between two or more non-metal atoms.
Metallic Bond
The attraction between positive metal ions in a regular lattice and delocalised electrons.
Lone Pair of Electrons
Two electrons that are unbounded in a molecule.
Molecule
Two or more atoms covalently bonded together.
Diatomic
Two atoms covalently bonded in a molecule.
Alloy
A mixture of two or more elements, at least one of which is a metal, and the resulting mixture has metallic properties.
Malleable
Can be hammered into shape.
Ductile
Can be drawn into a wire.
Sonorous
Can produce a ringing sound.
Lustrous
Shiny when freshly cut.
Allotropes
Different forms of the same element in the same physical state.
Precipitate
A solid which forms when two solutions mix.
Reliability
Whether or not the same result could be obtained if the experiment was repeated.
Validity
Whether or not the test fulfils the purpose of which it was carried out.
Ionic Equation
The equation to show the reaction between a positive ion and a negative ion to form a compound. Spectator ions are cancelled.
Indicator
A chemical which is one colour in an acid and a different colour in an alkali.
Acid
A substance which dissolves in water to produce hydrogen ions. H+(aq)
Strong Acid
An acid which is completely ionised in water.
Weak Acid
An acid which is only partially ionised in water.
Alkali
A soluble base which dissolves in water to produce hydroxide ions.
Strong Alkali
An alkali which is completely ionised in water.
Weak Alkali
An alkali which is only partially ionised in water.
Base
A metal oxide or metal hydroxide. OH-(aq)
Neutralisation
The reaction between the hydrogen ions of an acid and the hydroxide ions of an alkali to produce water. H+(aq) + OH-(aq) --> H2O(l)
Exothermic Reaction
A chemical reaction that releases heat.
Endothermic Reaction
A chemical reaction that takes in heat.
Salt
A compound formed when some or all of the hydrogen ions in an acid are replaced by metal ions.
Molecular Ion
A charged particle containing more than one element.
Solvent
The liquid in which the solute dissolves.
Solute
The solid which dissolves in a solvent.
Solution
The mixture formed when a solute dissolves in a solvent.
Soluble
A substance which dissolves in a solvent.
Insoluble
A substance which does not dissolve in a solvent.
Anhydrous
A solid which does not contain water of crystallisation and is powdery.
Hydrated
A solid which contains water of crystallisation and is crystalline.
Dehydration
The removal of water of crystallisation from a compound.
Solubility
The mass of solute in grads needed to saturate 100 grams of water at a particular temperature.
Saturated Solution
One in which the maximum amount of solute possible has dissolved in the solvent at a particular temperature.
Residue
The solid remaining in the filter paper during filtration.
Filtrate
The liquid that passes through the filter paper during filtration.
Distillate
The liquid collected during distillation.
Miscible
Two liquids that mix together.
Imiscible
Two liquids that do not mix together.
Group
A vertical column in the periodic table.
Period
A horizontal row in the periodic table.
Melting Point
The temperature at which a solid is changed to a liquid on heating.
Boiling Point
The temperature at which a liquid is changed to a gas on heating.
Evaporation
The change from liquid to gas on heating.
Condensation
The change from gas to liquid on cooling.
Melting
The change from solid to liquid on heating.
Freezing
The change from liquid to solid on cooling.
Sublimation
The direct change from solid to gas, on heating, without passing through the liquid state.
Displacement Reaction
One in which the more reactive element will displace the less reactive element from a solution of its compounds.
ionic bonding (non-metal/metal) physical properties
large lattice structure; -form crystalline solids -high melting point -hard -conducts electricity in the liquid state
covalent bonding (non-metals)
-low melting point -most are insoluble in water -doesn't conduct electricity
giant covalent bonding- diamond
very strong giant covalent bonds; -hard -high melting point -insoluble in water
giant covalent bonding- graphite
very strong giant covalent bonds; -(atoms are in layers) lubricant + pencils -soft high melting point only non-metal that can conduct electricity
giant covalent bonding- graphene
a single layer, one atom thick of graphite arranged in a honey-comb structure; -ultra-light -can conduct electricity -flexible -transparent
metals can conduct electrity
-in metal atoms, the outer electrons are free to move = they are delocalised, this is why metals, even when in the liquid state, can conduct electricity
bonding in metals
-very strong, due to the attraction between the positive ions, which are in a regular lattice and the delocalised ions
Group 1 - alkali metals
-very reactive in water -soft -shiny when cut -tarnishes in the air -low density stored in oil
Group 2 - alkaline earth metals
-less reactive than group 1 -hard
Group 7 - halogens
-toxic -coloured
Group 0 (8)
-inert -colorless -glow when electricity passes through them
test for chlorine (green gas)
-using damp universal indicator paper -will turn red (acidic properties) -bleach it white
sublimation (goes form the solid to the the gas state without becoming liquid) of iodne
-heat the iodine and it will turn to gas -the evaporating dish is filled with ice, to cool the gas and allow the solid iodine to form I2(s)->I2(g)
when halogens react...
they will gain one electron to obtain a full outer shell, an anion is formed = explained using half equation
half-equation; -flourine, - iodine, -bromine, -chlorine
F+e- -> F- = pale yellow I+e- -> I- = grey solid, purple gas Br+e- -> Br- = red brown Cl+e- ->Cl- = pale green
-copper (ii) oxide -copper (ii) carbonate -hydrated copper (ii) sulfate -anhydrous copper (ii) sulfate
-black -green -blue -white
-Hydrochloric acid (weakest) -Sulfuric acid (strongest) -Nitric acid (mid-strength)
-HCl -H2SO4 -HNO3
when metal react in acid, a salt and hydrogen are formed, this isn't a neutralisation reaction as water isn't formed;
2H2 + O2 --> 2H2O Hydrogen + oxygen --> water
in the reaction of metals in acid, salts are formed
salt is formed because the hydrogen ions ions in the acid are replaced by the metal ions. This is a displacement reaction.
metal ions
lithium - crimson sodium - orange/yellow potassium - lilac calcium - brick red copper green/blue
Note
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