● Keywords are in bold
● Definitions are highlighted in blue
● Equations are highlighted in red
Paper 1 (50%)
Topic 1: Atomic structures and the periodic table
Atoms, Elements and Compounds
● Element - a substance that cannot be chemically broken down into simpler
substances
○ We cannot change one element into another
● Compound - composed of many identical molecules chemically bonded
together
○ They bond in fixed ratios and can be represented in a chemical formula
● Pure - a pure substance in chemistry means it contains only one element or one
compound, with a fixed boiling point
Mixtures
● Mixture - two or more different substances which aren’t chemically combined
○ The chemical properties of each substance in the mixture stay
unchanged
○ They can be separated by physical processes (e.g filtration and
chromatography)
History of the Atom
Atomic Theory (500 B.C)
● Suggested that small particles make up everything
● They are separated by empty space
● Proposed by Democritus
John Dalton (1800s)
● Suggested that atoms were like tiny spheres
● He said that different elements are made up of different types of spheres
J.J Thompson and the Plum Pudding model (1897)
● He said that atoms couldn’t be solid spheres
● He said that they must contain negatively charged particles
, ● He proposed that the atom was a general ball of positive charge with
negative particles stuck in it
Ernest Rutherford and the Nuclear Model (1909)
● Fired positively charged alpha particles at a thin sheet of gold
● According to Thompson’s theory, they should go straight through
● However, some particles were deflected
● He suggested that there was some sort of compact nucleus, which contained
all of the positive charge and that the negative charge was in some sort of
cloud
Niels Bohr (1913)
● He suggested that the electrons orbited the nucleus and were held in shells
James Chadwick
● Provided evidence for the existence of neutral particles in the nucleus -
neutrons
Atomic Structure
Subatomic particle Relative mass Charge
Proton 1 +1
Neutron 1 0
Electron 0 -1
● Atomic number - number of protons
● Atomic mass / mass number - number of protons + number of neutrons
● Shielding - the number of shells between the nucleus and outer shell
Isotopes
● Isotope - atoms of the same element with the same number of protons, but
different number of neutrons
● They react in the same way, as their electron configuration is the same
Electron Structure
● Electrons orbit the nucleus in shells, which gradually get further away from the
nucleus
● Each shell can hold a maximum number of electrons
, ● The shells closest to the nucleus are filled first
● The first shell can hold 2, the others can hold 8
● Sodium has 11 electrons - its electron configuration is 2.8.1
Modern Periodic Table
● Elements are ordered by atomic number (the number of protons)
● Elements with similar properties are in columns, called groups
○ They have the same number of electrons in their outer shell
● Scientists first attempted to sort the elements by atomic weight
● This didn’t work because it meant that some elements were placed in
inappropriate groups due to their properties
● Mendeleev noticed that there was a pattern in the chemical properties
● He started a new line after the pattern was repeated
● He also left gaps between elements that he thought hadn’t been discovered
yet
● These predictions came true when new elements were discovered
● This prompted other scientists to support his idea
Metals and Non-metals
● Metal - an element that reacts to form positive ions
● Non-metal - an element that reacts to form negative ions
● Metals are on the left side of the periodic table and non-metals are on the right
Group 0 - Noble Gases
● Have a full outer shell
○ This makes them very unreactive, or inert
● Their densities and boiling points increase as we go down the group
● They exist as single atoms - monatomic
● Their unreactivity makes them useful
Group 1 - Alkali Metals
● They have one electron in their outer shell
● The reactivity increases as we go down the group
○ This is because it is easier to lose the electrons, as they are further away
from the nucleus, meaning less electrostatic attraction
● We store alkali metals under oil to prevent water vapour and oxygen reacting
with them
, Properties
● Soft
● Low densities
● Low melting points
● Alkali metal + water → Alkali metal hydroxide + hydrogen
● 2Li (s) + 2H2O (l) →2LiOH (aq) + H2 (g)
● Alkali metal + chlorine → Alkali metal chloride
● 2Li (s) + Cl2 (g) →2LiCl (s)
● Alkali metal + oxygen → Alkali metal oxide
● 4Li (s) + O2 (g) →2Li2O (s)
Group 7 - Halides
● They are classed as non-metals
● They exist in pairs of atoms - diatomic
● They reactivity decreases as we go down the group
● The relative atomic mass and boiling points increase as we go down the
group
● When made into a salt, the ine becomes ide
● A more reactive halogen can displace a less reactive one from its salt
● Halogen + metal → Metal halide
● 2Al (s) + 3Cl2 (g) → AlCl3 (s)
● This reaction is exothermic and often releases noticeable heat
● Halogen + Hydrogen→ Hydrogen halide
● H2 (g) + Cl2 → 2HCl (g)
Uses of Elements from Groups 1, 7 and 8
Group Element Uses
Lithium Can treat disorders
1
Sodium Nutrient in the body
Potassium Nerve and muscle contraction
Fluorine Toothpastes
● Definitions are highlighted in blue
● Equations are highlighted in red
Paper 1 (50%)
Topic 1: Atomic structures and the periodic table
Atoms, Elements and Compounds
● Element - a substance that cannot be chemically broken down into simpler
substances
○ We cannot change one element into another
● Compound - composed of many identical molecules chemically bonded
together
○ They bond in fixed ratios and can be represented in a chemical formula
● Pure - a pure substance in chemistry means it contains only one element or one
compound, with a fixed boiling point
Mixtures
● Mixture - two or more different substances which aren’t chemically combined
○ The chemical properties of each substance in the mixture stay
unchanged
○ They can be separated by physical processes (e.g filtration and
chromatography)
History of the Atom
Atomic Theory (500 B.C)
● Suggested that small particles make up everything
● They are separated by empty space
● Proposed by Democritus
John Dalton (1800s)
● Suggested that atoms were like tiny spheres
● He said that different elements are made up of different types of spheres
J.J Thompson and the Plum Pudding model (1897)
● He said that atoms couldn’t be solid spheres
● He said that they must contain negatively charged particles
, ● He proposed that the atom was a general ball of positive charge with
negative particles stuck in it
Ernest Rutherford and the Nuclear Model (1909)
● Fired positively charged alpha particles at a thin sheet of gold
● According to Thompson’s theory, they should go straight through
● However, some particles were deflected
● He suggested that there was some sort of compact nucleus, which contained
all of the positive charge and that the negative charge was in some sort of
cloud
Niels Bohr (1913)
● He suggested that the electrons orbited the nucleus and were held in shells
James Chadwick
● Provided evidence for the existence of neutral particles in the nucleus -
neutrons
Atomic Structure
Subatomic particle Relative mass Charge
Proton 1 +1
Neutron 1 0
Electron 0 -1
● Atomic number - number of protons
● Atomic mass / mass number - number of protons + number of neutrons
● Shielding - the number of shells between the nucleus and outer shell
Isotopes
● Isotope - atoms of the same element with the same number of protons, but
different number of neutrons
● They react in the same way, as their electron configuration is the same
Electron Structure
● Electrons orbit the nucleus in shells, which gradually get further away from the
nucleus
● Each shell can hold a maximum number of electrons
, ● The shells closest to the nucleus are filled first
● The first shell can hold 2, the others can hold 8
● Sodium has 11 electrons - its electron configuration is 2.8.1
Modern Periodic Table
● Elements are ordered by atomic number (the number of protons)
● Elements with similar properties are in columns, called groups
○ They have the same number of electrons in their outer shell
● Scientists first attempted to sort the elements by atomic weight
● This didn’t work because it meant that some elements were placed in
inappropriate groups due to their properties
● Mendeleev noticed that there was a pattern in the chemical properties
● He started a new line after the pattern was repeated
● He also left gaps between elements that he thought hadn’t been discovered
yet
● These predictions came true when new elements were discovered
● This prompted other scientists to support his idea
Metals and Non-metals
● Metal - an element that reacts to form positive ions
● Non-metal - an element that reacts to form negative ions
● Metals are on the left side of the periodic table and non-metals are on the right
Group 0 - Noble Gases
● Have a full outer shell
○ This makes them very unreactive, or inert
● Their densities and boiling points increase as we go down the group
● They exist as single atoms - monatomic
● Their unreactivity makes them useful
Group 1 - Alkali Metals
● They have one electron in their outer shell
● The reactivity increases as we go down the group
○ This is because it is easier to lose the electrons, as they are further away
from the nucleus, meaning less electrostatic attraction
● We store alkali metals under oil to prevent water vapour and oxygen reacting
with them
, Properties
● Soft
● Low densities
● Low melting points
● Alkali metal + water → Alkali metal hydroxide + hydrogen
● 2Li (s) + 2H2O (l) →2LiOH (aq) + H2 (g)
● Alkali metal + chlorine → Alkali metal chloride
● 2Li (s) + Cl2 (g) →2LiCl (s)
● Alkali metal + oxygen → Alkali metal oxide
● 4Li (s) + O2 (g) →2Li2O (s)
Group 7 - Halides
● They are classed as non-metals
● They exist in pairs of atoms - diatomic
● They reactivity decreases as we go down the group
● The relative atomic mass and boiling points increase as we go down the
group
● When made into a salt, the ine becomes ide
● A more reactive halogen can displace a less reactive one from its salt
● Halogen + metal → Metal halide
● 2Al (s) + 3Cl2 (g) → AlCl3 (s)
● This reaction is exothermic and often releases noticeable heat
● Halogen + Hydrogen→ Hydrogen halide
● H2 (g) + Cl2 → 2HCl (g)
Uses of Elements from Groups 1, 7 and 8
Group Element Uses
Lithium Can treat disorders
1
Sodium Nutrient in the body
Potassium Nerve and muscle contraction
Fluorine Toothpastes
