Elements of Life
28 May 2024 14:49
EL1 Atomic structure, mass spectrometry, and nuclear fusion
EL4 Periodicity
Discovering the atom:
Particle Mass on relative atomic mass scale Charge Location in atom Groups are the vertical columns on the periodic table and periods are the horizontal rows on the periodic table. Periodicity is the occurrence
John Dalton 1803 - atoms are tiny spheres that cannot be divided
proton 1 +1 nucleus of periodic patterns within these.
JJ Thomson - plum pudding model, the atom is a ball of positive charge neutron 1 0 nucleus
with negative electrons embedded in it electron 0.00055 -1 shells Melting points and boiling points are determined by the strength of the intermolecular Group/Element Subshell block Ionic charge
forces
Ernest Rutherford 1909 - fired positive alpha particles at gold foil and Group 1 s- +1
The group number determines the number of outer electrons, which in turn determines
proved the nucleus, he proposed the nucleus model Isotopes are the same element with different number of neutrons but the chemical properties of that element. Elements with full outer shells are called closed Group 2 s- +2
the same number of protons and electrons. Elements usually exist as shell arrangements and are very stable. Group 3 p- -1
Neils Bohr - electrons orbit the nucleus in shells with different energy isotopes, so an average of all its relative isotopic masses is taken to find
levels, the nucleus also contains small positive particles called protons Group 4 p- -2
relative atomic mass. S- and P- block ions:
An element where the s-subshell is being filled is called a s-block element, the same with p-, Aluminium p- +3
Jamie Chadwick 1932 - discovered neutrons d- and f- subshells.
Nuclear Fusion:
Mass Spectrometry Two light atomic nuclei fuse together to form a single heavier nucleus
Mass spec measures atomic or molecular masses, and the relative of a new element , releasing enormous amounts of energy. This cannot
abundance of isotopes in the element. In mass spec, molecules are happen on Earth as at normal temperature nuclei repel, but in a star EL5 Covalent bonding and shapes of molecules
ionised to cations and separated according to mass. they move much quicker so the repulsion is overcome.
Covalent bonding:
Covalent bonding is the sharing of electrons between two non-metal elements. When When drawing structures, single
sharing one pair it is a single covalent bond, when sharing two it’s a double, and three solid lines are drawn to show a bond
is a triple bond. When both electrons come from the same atom it is called a dative on the same plane, dashed
covalent bond. Compounds with simple covalent bonding have low melting and boiling triangular lines mean the bond is
points , low conductivity and do not dissolve readily in water. BEHIND the plane of the drawing,
and a solid triangular line shows the
Similar charges repel, so when bonding regions of electron density arrange themselves bond is INFRONT of the plane of
to be as far apart from the others as possible to form different structures depending the drawing.
on the number and strength of repulsion, lone pairs can skew a structure as they repel
more strongly than bonded pairs.
EL2 Wave and Particle theory of light. Structure Descriptions Bond angles Example and diagram
Methane, CH4
Wave theory:
This model shows light is a form of electromagnetic radiation, electromagnetic
radiation travels at the speed of light for all wavelengths, 3.00 x 108 ms-1 . Tetrahedral Four atoms bonded to a central atom, positioning and angles 109.5 degrees
affected by lone pairs (see table adjacent)
Speed of light, c = wavelength, λ x frequency, v
Particle theory: Beryllium chloride,
This model shows light as a stream of energy packets called photons. The equation BeCl2
links energy, frequency, and Planck constant which is 6.63 x 10-34 Js-1 Linear Two atoms bonded to one atom in a straight line 180 degrees
Energy of a photon, e = Planck constant, h x frequency, v
Boron fluoride, BF3
Bohr's theory:
When excited, electrons jump into higher energy levels, then when they return to Planar Three atoms spaced regularly around a central atom 120 degrees
The energy levels diagram and triangular
their original state they emit electromagnetic radiation giving off an emission spectra.
corresponding emission spectra of the
The sequence of lines in an emission spectra is characteristic of the atoms of the
Lyman series, which is the emission
element, and the intensities correspond to abundance. Bohr also relied on the
spectra related to energy levels in the Phosphorous
quantisation of energy.
hydrogen atom pentachloride
PCl5
Main Points:
Bipyramidal Five groups around a central atom with electrons at 5 120 degrees or 90 degrees
- The electron in hydrogen exists only in definite energy levels
corners depending on position
- A photon of light is emitted/absorbed when an electron changes energy levels
- the energy of a photon is equal to the difference between two energy levels
SF6
EL3 Shells, subshells, and orbitals
Octahedral Six groups of electrons around a central atom (metal ions 90 degrees
Shell number, n Number of electrons with six ligands)
1 2
2 8
3 18
4 24 Tetrahedral structures can vary depending on lone pairs, which repel more strongly
and can alter bond angles and structures.
Each shell in an atom has consequent
When filling shells and subshells, they are filled in accordance to their energy levels, 4s
subshells with different shapes and Number of groups of electron Types of groups Bond angles Example
is filled AND emptied before 3d as it has a lower energy level despite being in a higher
capacities for electrons. Within those
shell. Electrons in boxes must be filled separately first with electrons in individual 4 4 single covalent bonds 109.5 degrees Methane
subshells are orbitals, each orbital can hold 2
boxes before pairing them up as the opposite spin repels apart
electrons of opposite spin. 4 3 single covalent bonds 107.0 degrees Ammonia
1 lone pair of electrons
Subshell Number of orbitals Number of electrons 4 2 single covalent bonds 104.5 degrees Water
S- orbitals are spherical P-orbitals are dumbbell shaped for all axis 2 lone pairs of electrons
s 1 2
p 3 6
d 5 10
f 7 14
EL7 Bonding, structures, properties, and precipitates.
EL6 Ar, Mr, percentage yield and balancing equations
Ionic bonding:
Ionic bonding is when one atom in the bond will either lose/gain an electron and Ionic bonding properties:
One mole is the number of particles as there is the number of atoms in Water of crystallisation: -Usually solids
become bonded through electrostatic attraction. This is between a metal and non-
12g of carbon-12. One mole of atoms/molecules will always contain the Some ionic lattices include molecules of water, these water molecules -Lattice structure of repeating positive and negative
metal. A positive ion is called a cation, and a negative ion is called an anion. Ionic
same number of units, this number is Avogadro's Constant which is 6.02 x are fitted into the ionic lattice in a regular manner and are called ions
bonds are formed if the overall energy change for the reaction is favourable.
1023. The empirical formula is often used in moles calculations, it is the water of crystallisation and shown as a bold dot within the molecular -Often form regular crystals (and salts)
very simplest ratio of elements in the compound e.g. C2H6 --> CH3 formula as shown below. -High melting point and boiling point
To calculate the formula of a hydrated compound, the salt must be Cations Anions
-Conduct electricity when molten
Number of moles = mass of substance/relative formula mass heated to a constant mass, then the formula can be determined as +1 +2 +3 -1 -2
(Moles = mass/Mr) the water has evaporated.
Hydrogen Magnesium Aluminium Fluoride Oxide O2-
Ionic substances in solution:
Percentage Yield: Lithium Calcium Iron (III) Chloride Carbonate CO32-
Most ionic substances dissolve readily in water, however
Percentage yield is the amount of products made compared to the full Sodium Barium Bromide Sulphate SO42-
When writing equations for reaction, the equation must be balanced some are insoluble and form precipitates.
amount that should have been made.
in order to show the moles involved in a reaction and accurately carry Potassium Iron (II) Iodide -Barium, calcium, lead and silver sulphates
out calculations. -Silver and lead halides
percentage yield % = actual yield/ theoretical yield x 100 Ammonium NH4+ Copper (II) Hydroxide
-All metal carbonates
Zinc Nitrate NO 3- -Metal hydroxides (excluding group 1 and ammonium
Factors affecting percentage yield:
Lead (II) Hydrogen carbonate HCO 3- hydroxide)
- Impurities in reactants
- Changes in temperature or pressure
- Side reactions occurring
Making ionic salts:
- Loss of products from reaction vessel Metallic bonding:
- If the reaction is an equilibrium system Metallic bonding is in a lattice structure of positive metal ions in a sea of delocalised
Acid + Alkali --> salt + water
electrons. This means they conduct electricity and heat very well. They are held
EL8 Group 1 and 2 chemistry together by the attraction of metal cations to the delocalised electrons and have high
Acid + base --> salt + water
melting and boiling points.
Acids and bases: Acids and Bases in solution: Acid + carbonate --> salt + water + carbon dioxide
(Giant) Covalent networks:
Acid - a compound that dissociates in water to produce hydrogen In solution, water will act as a base and accept H+ ions, becoming the
Covalent networks have very high melting and boiling points, they do not conduct
ion, it then donates the H+ ions and becomes a proton donor oxonium ion, which is very common and present in every solution of an Acid + metal --> salt + hydrogen
electricity or heat and are insoluble.
Base - a compound that reacts with an acid to produce water and a acid in water, it is in every acidic solution. The oxonium ion can act as
salt, it accepts the H+ ions and becomes a proton acceptor an acid and donate H+. H+(aq) forms in solution when an acid
Alkali - a base that forms OH- ions in solution dissolves in water
The theory of H+ transfer is called the Brønstead-Lowry theory of
acids and bases. HCl(aq) + H2O(l) --> H3O+(aq) + Cl-(aq)
HCl donates H+ to H2O which then forms the oxonium ion, H3O+
concentration, mol/dm-3 = moles/volume, dm3
1 dm3 = 1000 cm3 1 cm3 = 0.001 dm 3
Chemistry Page 1
28 May 2024 14:49
EL1 Atomic structure, mass spectrometry, and nuclear fusion
EL4 Periodicity
Discovering the atom:
Particle Mass on relative atomic mass scale Charge Location in atom Groups are the vertical columns on the periodic table and periods are the horizontal rows on the periodic table. Periodicity is the occurrence
John Dalton 1803 - atoms are tiny spheres that cannot be divided
proton 1 +1 nucleus of periodic patterns within these.
JJ Thomson - plum pudding model, the atom is a ball of positive charge neutron 1 0 nucleus
with negative electrons embedded in it electron 0.00055 -1 shells Melting points and boiling points are determined by the strength of the intermolecular Group/Element Subshell block Ionic charge
forces
Ernest Rutherford 1909 - fired positive alpha particles at gold foil and Group 1 s- +1
The group number determines the number of outer electrons, which in turn determines
proved the nucleus, he proposed the nucleus model Isotopes are the same element with different number of neutrons but the chemical properties of that element. Elements with full outer shells are called closed Group 2 s- +2
the same number of protons and electrons. Elements usually exist as shell arrangements and are very stable. Group 3 p- -1
Neils Bohr - electrons orbit the nucleus in shells with different energy isotopes, so an average of all its relative isotopic masses is taken to find
levels, the nucleus also contains small positive particles called protons Group 4 p- -2
relative atomic mass. S- and P- block ions:
An element where the s-subshell is being filled is called a s-block element, the same with p-, Aluminium p- +3
Jamie Chadwick 1932 - discovered neutrons d- and f- subshells.
Nuclear Fusion:
Mass Spectrometry Two light atomic nuclei fuse together to form a single heavier nucleus
Mass spec measures atomic or molecular masses, and the relative of a new element , releasing enormous amounts of energy. This cannot
abundance of isotopes in the element. In mass spec, molecules are happen on Earth as at normal temperature nuclei repel, but in a star EL5 Covalent bonding and shapes of molecules
ionised to cations and separated according to mass. they move much quicker so the repulsion is overcome.
Covalent bonding:
Covalent bonding is the sharing of electrons between two non-metal elements. When When drawing structures, single
sharing one pair it is a single covalent bond, when sharing two it’s a double, and three solid lines are drawn to show a bond
is a triple bond. When both electrons come from the same atom it is called a dative on the same plane, dashed
covalent bond. Compounds with simple covalent bonding have low melting and boiling triangular lines mean the bond is
points , low conductivity and do not dissolve readily in water. BEHIND the plane of the drawing,
and a solid triangular line shows the
Similar charges repel, so when bonding regions of electron density arrange themselves bond is INFRONT of the plane of
to be as far apart from the others as possible to form different structures depending the drawing.
on the number and strength of repulsion, lone pairs can skew a structure as they repel
more strongly than bonded pairs.
EL2 Wave and Particle theory of light. Structure Descriptions Bond angles Example and diagram
Methane, CH4
Wave theory:
This model shows light is a form of electromagnetic radiation, electromagnetic
radiation travels at the speed of light for all wavelengths, 3.00 x 108 ms-1 . Tetrahedral Four atoms bonded to a central atom, positioning and angles 109.5 degrees
affected by lone pairs (see table adjacent)
Speed of light, c = wavelength, λ x frequency, v
Particle theory: Beryllium chloride,
This model shows light as a stream of energy packets called photons. The equation BeCl2
links energy, frequency, and Planck constant which is 6.63 x 10-34 Js-1 Linear Two atoms bonded to one atom in a straight line 180 degrees
Energy of a photon, e = Planck constant, h x frequency, v
Boron fluoride, BF3
Bohr's theory:
When excited, electrons jump into higher energy levels, then when they return to Planar Three atoms spaced regularly around a central atom 120 degrees
The energy levels diagram and triangular
their original state they emit electromagnetic radiation giving off an emission spectra.
corresponding emission spectra of the
The sequence of lines in an emission spectra is characteristic of the atoms of the
Lyman series, which is the emission
element, and the intensities correspond to abundance. Bohr also relied on the
spectra related to energy levels in the Phosphorous
quantisation of energy.
hydrogen atom pentachloride
PCl5
Main Points:
Bipyramidal Five groups around a central atom with electrons at 5 120 degrees or 90 degrees
- The electron in hydrogen exists only in definite energy levels
corners depending on position
- A photon of light is emitted/absorbed when an electron changes energy levels
- the energy of a photon is equal to the difference between two energy levels
SF6
EL3 Shells, subshells, and orbitals
Octahedral Six groups of electrons around a central atom (metal ions 90 degrees
Shell number, n Number of electrons with six ligands)
1 2
2 8
3 18
4 24 Tetrahedral structures can vary depending on lone pairs, which repel more strongly
and can alter bond angles and structures.
Each shell in an atom has consequent
When filling shells and subshells, they are filled in accordance to their energy levels, 4s
subshells with different shapes and Number of groups of electron Types of groups Bond angles Example
is filled AND emptied before 3d as it has a lower energy level despite being in a higher
capacities for electrons. Within those
shell. Electrons in boxes must be filled separately first with electrons in individual 4 4 single covalent bonds 109.5 degrees Methane
subshells are orbitals, each orbital can hold 2
boxes before pairing them up as the opposite spin repels apart
electrons of opposite spin. 4 3 single covalent bonds 107.0 degrees Ammonia
1 lone pair of electrons
Subshell Number of orbitals Number of electrons 4 2 single covalent bonds 104.5 degrees Water
S- orbitals are spherical P-orbitals are dumbbell shaped for all axis 2 lone pairs of electrons
s 1 2
p 3 6
d 5 10
f 7 14
EL7 Bonding, structures, properties, and precipitates.
EL6 Ar, Mr, percentage yield and balancing equations
Ionic bonding:
Ionic bonding is when one atom in the bond will either lose/gain an electron and Ionic bonding properties:
One mole is the number of particles as there is the number of atoms in Water of crystallisation: -Usually solids
become bonded through electrostatic attraction. This is between a metal and non-
12g of carbon-12. One mole of atoms/molecules will always contain the Some ionic lattices include molecules of water, these water molecules -Lattice structure of repeating positive and negative
metal. A positive ion is called a cation, and a negative ion is called an anion. Ionic
same number of units, this number is Avogadro's Constant which is 6.02 x are fitted into the ionic lattice in a regular manner and are called ions
bonds are formed if the overall energy change for the reaction is favourable.
1023. The empirical formula is often used in moles calculations, it is the water of crystallisation and shown as a bold dot within the molecular -Often form regular crystals (and salts)
very simplest ratio of elements in the compound e.g. C2H6 --> CH3 formula as shown below. -High melting point and boiling point
To calculate the formula of a hydrated compound, the salt must be Cations Anions
-Conduct electricity when molten
Number of moles = mass of substance/relative formula mass heated to a constant mass, then the formula can be determined as +1 +2 +3 -1 -2
(Moles = mass/Mr) the water has evaporated.
Hydrogen Magnesium Aluminium Fluoride Oxide O2-
Ionic substances in solution:
Percentage Yield: Lithium Calcium Iron (III) Chloride Carbonate CO32-
Most ionic substances dissolve readily in water, however
Percentage yield is the amount of products made compared to the full Sodium Barium Bromide Sulphate SO42-
When writing equations for reaction, the equation must be balanced some are insoluble and form precipitates.
amount that should have been made.
in order to show the moles involved in a reaction and accurately carry Potassium Iron (II) Iodide -Barium, calcium, lead and silver sulphates
out calculations. -Silver and lead halides
percentage yield % = actual yield/ theoretical yield x 100 Ammonium NH4+ Copper (II) Hydroxide
-All metal carbonates
Zinc Nitrate NO 3- -Metal hydroxides (excluding group 1 and ammonium
Factors affecting percentage yield:
Lead (II) Hydrogen carbonate HCO 3- hydroxide)
- Impurities in reactants
- Changes in temperature or pressure
- Side reactions occurring
Making ionic salts:
- Loss of products from reaction vessel Metallic bonding:
- If the reaction is an equilibrium system Metallic bonding is in a lattice structure of positive metal ions in a sea of delocalised
Acid + Alkali --> salt + water
electrons. This means they conduct electricity and heat very well. They are held
EL8 Group 1 and 2 chemistry together by the attraction of metal cations to the delocalised electrons and have high
Acid + base --> salt + water
melting and boiling points.
Acids and bases: Acids and Bases in solution: Acid + carbonate --> salt + water + carbon dioxide
(Giant) Covalent networks:
Acid - a compound that dissociates in water to produce hydrogen In solution, water will act as a base and accept H+ ions, becoming the
Covalent networks have very high melting and boiling points, they do not conduct
ion, it then donates the H+ ions and becomes a proton donor oxonium ion, which is very common and present in every solution of an Acid + metal --> salt + hydrogen
electricity or heat and are insoluble.
Base - a compound that reacts with an acid to produce water and a acid in water, it is in every acidic solution. The oxonium ion can act as
salt, it accepts the H+ ions and becomes a proton acceptor an acid and donate H+. H+(aq) forms in solution when an acid
Alkali - a base that forms OH- ions in solution dissolves in water
The theory of H+ transfer is called the Brønstead-Lowry theory of
acids and bases. HCl(aq) + H2O(l) --> H3O+(aq) + Cl-(aq)
HCl donates H+ to H2O which then forms the oxonium ion, H3O+
concentration, mol/dm-3 = moles/volume, dm3
1 dm3 = 1000 cm3 1 cm3 = 0.001 dm 3
Chemistry Page 1
