Chemistry paper 1 content
Chemical reactions
Element – a substance containing one type of atom
Compound – a substance containing two or more different types of
atoms, chemically bonded.
Ions - positive (cations) forms when an atom looses electrons, negative
(anions) form when an atom gains an electron.
Due to conservation of mass atoms can neither be created or destroyed
in reactions, equations must be balanced.
States of matter
Energy (heat) is needed to overcome the (electrostatic) forces of
attraction between particles to melt/evaporating.
Solid – gas = sublimation gas – liquid = condensing
Liquid – gas = evaporating/boiling liquid – solid = freezing
Solid – liquid = melting
Mixtures and separation techniques
A mixture consists of different substances not chemically bonded .
Filtration removes large insoluble particles from a liquid
Evaporation leaves behind crystals of dissolved ed substance if heated
gently.
Distillation involves condensing the evaporated solvent and collecting it.
Fractional distillation can separate liquids due to their different boiling
points.
Chromatography causes substance to rise up paper due to capillary
action. lighter particles move further up.
Atomic structure
Atom consists of electrons, nucleus (protons and neutrons)
Proton --- charge of +1 --- mass of 1
Neutron --- charge of 0 --- mass of 1
Electron --- charge of –1 --- mass of 1>
, 1803 John Daulton popularised the theory that matter is made of
indivisible particles.
1897 JJ Thompson created the plum pudding model
1909 Ernest rutherford discovered that the nucleus was small and
positivley charged by finding that most alpha particles went straight
through a gold leaf very few deflected back.
1913 Neils Bohr deduced that electrons exist in shells.
1932 James Chadwick determined that the nucleus must contain
neurons as well as protons
Atomic number is the number of protons in a nucleus the bottom number
on the element.
An atom must also have this number of electrons in order for it to be
neutral, if not it is a ion.
Mass number = number of protons + neutrons in a nucleus.
An isotope is the same element with different number of neutrons
Average mass = total mass of 100 atoms / 100
Periodic table
Elements first ordered according to their atomic weight even though
grouped together due to having small properties.
Dimitri Mendeleev created the periodic table with gaps in which we
predicted was for elements which haven't been discovered yet, in time
this table was proved largely correct and is the basis of the modern
periodic table.
All elements contain 2,8,8 2 electrons on their outer shells.
Except transition metals these are 2,8,2
Metals and non-metals are separated form boron in a staircase motion.
metals donate electrons to gain an empty outer shell forming a positive
ion. Non-metals always gain electrons for they want a full outer shell to
create a negative ion or can share electrons in bonding.
Group 1 - Alkali metals ( + 1 ) they get more reactive as they travel down
the group. They can react with water to create alkalis.
Group 7 – halogens ( - 1 ) they get less reactive as you travel down the
group of elements.
Chemical reactions
Element – a substance containing one type of atom
Compound – a substance containing two or more different types of
atoms, chemically bonded.
Ions - positive (cations) forms when an atom looses electrons, negative
(anions) form when an atom gains an electron.
Due to conservation of mass atoms can neither be created or destroyed
in reactions, equations must be balanced.
States of matter
Energy (heat) is needed to overcome the (electrostatic) forces of
attraction between particles to melt/evaporating.
Solid – gas = sublimation gas – liquid = condensing
Liquid – gas = evaporating/boiling liquid – solid = freezing
Solid – liquid = melting
Mixtures and separation techniques
A mixture consists of different substances not chemically bonded .
Filtration removes large insoluble particles from a liquid
Evaporation leaves behind crystals of dissolved ed substance if heated
gently.
Distillation involves condensing the evaporated solvent and collecting it.
Fractional distillation can separate liquids due to their different boiling
points.
Chromatography causes substance to rise up paper due to capillary
action. lighter particles move further up.
Atomic structure
Atom consists of electrons, nucleus (protons and neutrons)
Proton --- charge of +1 --- mass of 1
Neutron --- charge of 0 --- mass of 1
Electron --- charge of –1 --- mass of 1>
, 1803 John Daulton popularised the theory that matter is made of
indivisible particles.
1897 JJ Thompson created the plum pudding model
1909 Ernest rutherford discovered that the nucleus was small and
positivley charged by finding that most alpha particles went straight
through a gold leaf very few deflected back.
1913 Neils Bohr deduced that electrons exist in shells.
1932 James Chadwick determined that the nucleus must contain
neurons as well as protons
Atomic number is the number of protons in a nucleus the bottom number
on the element.
An atom must also have this number of electrons in order for it to be
neutral, if not it is a ion.
Mass number = number of protons + neutrons in a nucleus.
An isotope is the same element with different number of neutrons
Average mass = total mass of 100 atoms / 100
Periodic table
Elements first ordered according to their atomic weight even though
grouped together due to having small properties.
Dimitri Mendeleev created the periodic table with gaps in which we
predicted was for elements which haven't been discovered yet, in time
this table was proved largely correct and is the basis of the modern
periodic table.
All elements contain 2,8,8 2 electrons on their outer shells.
Except transition metals these are 2,8,2
Metals and non-metals are separated form boron in a staircase motion.
metals donate electrons to gain an empty outer shell forming a positive
ion. Non-metals always gain electrons for they want a full outer shell to
create a negative ion or can share electrons in bonding.
Group 1 - Alkali metals ( + 1 ) they get more reactive as they travel down
the group. They can react with water to create alkalis.
Group 7 – halogens ( - 1 ) they get less reactive as you travel down the
group of elements.
