CHEM1001 Fundamentals of Chemistry 1A NOTES
CHEM1001 Fundamentals of Chemistry 1A NOTES » Atomic Theory -
All matter consists of atoms – chemically indivisible particles of an element that cannot be created or destroyed Atoms of one element cannot be converted into atoms of another element Atoms of an element are identical and are different from atoms of any other element
» Matter -
Mixture (heterogeneous or homogenous) Pure substance (homogeneous) o Elements (contains atoms of only one type, refer to period table) o Molecules (2 or more atoms) o Compounds (2 or more elements combined in a unique ratio)
» Elements in Nature -
-
Noble Gases occur naturally as atoms: He, Ne, Ar, Kr, Xe, Rn Diatomic molecules: H2, N2, F2, O2, I2, Cl2, Br2 (Have No Fear Of Ice Cold Beer) Larger molecules: S8 Infinite aggregates: C, Cu, Fe, Ag
» Chemical Symbols -
One or two letters (1st is uppercase, 2nd is lowercase) E.g. C for carbon, Ca for calcium, Fe for iron (ferrum)
» Chemical Formulas -
Represent the atoms present E.g. methane is CH4, ammonia is NH3
Methane
Ammonia
» Chemical Equations -
Represent a change of one substance to another Word equation: methane + oxygen ! carbon dioxide + water Symbolic equation: CH4 + 2 O2 ! CO2 + 2 H2O
» States of Matter -
Different physical ways of packing particles A physical change is associated with a change of state A chemical change involves changing one substance into another
Page 1 of 45
» Physical v Chemical Change -
-
Physical change = substance alters its physical form but NOT its composition o Compound doesn’t change o Chemical bonds do not form or break o E.g. boiling water, freezing wax Chemical change = substance(s) is converted into a new substance(s) o Compound/allotrope changes o Chemical bonds form or break o E.g. burning of H2 with O2 to give H2O, reacting zinc with hydrochloric acid
» Physical Properties -
-
Properties that a substance shows by itself without changing or interacting with another substance o Colour o Melting point o Conductivity o Density o Surface tension Characteristics which belong to the substance itself, therefore, will always have that property
» Chemical Properties -
Properties of a substance that result in the formation of a new substance o Flammability o Corrosiveness o Reactivity with acid
» Properties of Matter -
An intensive property is independent of the amount of substance present e.g. pH An extensive property depends on the amount of substance present e.g. volume Page 2 of 45
» Atomic Structure -
Atoms are mostly empty space occupied by electrons All the positive charge and essentially all the mass lies in the centre – the nucleus The nucleus contains positively charge particles, protons, and uncharged neutrons Particle
Symbol
Proton Neutron Electron
Relative mass
Relative charge
p or p
+
1
+
n or n
0
1
0
-
1/1836
-
e or e
» Elements -
What determines element type? The number of protons in the nucleus of the atoms This is the atomic number, Z Atomic number gives the charge of the nucleus
» Atomic Symbol -
-
Atomic symbol, X, is uniquely related to the number of protons (atomic number, Z) o 2 protons (Z = 2) = helium = He o 8 protons (Z = 8) = oxygen = O o 92 protons (Z = 92) = uranium = U Atoms have no overall charge so atomic number = number of electrons
» Forces in Atoms -
Nucleons held together by the Strong Nuclear Force o Effective over short distances o Overcomes the repulsion between protons
» Cations and Anions -
-
Atoms can gain electrons to form anions o F + e- ! Fo O + 2e- ! O2o N + 3e- ! N3Atoms can lose electrons to form cations o Na ! Na+ + eo Mg ! Mg2+ + 2eo Al ! Al3+ + 3e-
Anion = a negative ion In ‘cation,’ the t looks like a plus (+)
» Electron Structures -
Group: number of electrons in outer shell/orbit Period: number of electron shells/orbits containing electrons Page 3 of 45
» Electromagnetic Radiation
-
Wavelength, λ, lambda o The distance between two adjacent identical points of the wave Frequency, ν, nu o The number of wave crests passing a given point per unit time All light waves travel at the same speed – the speed of light, c, is a constant
-
C = 2.998 x 108 ms-1 Wavelength and frequency are related to the speed of light
-
-
-
C = λν Radiation may have the same speed but the energy can vary Higher frequency means more rapidly oscillating waves which means higher energy Energy = Planck’s constant x frequency E = hv h = 6.626 x 10-34 Js
» Atomic Spectra -
-
When supplied with energy, an atom emits electromagnetic radiation of distinct frequencies, unique to that element – atomic emission spectrum Light emitted from a hydrogen lamp has only a few lines o Only light of certain energies is emitted o The pattern of lines is unique to hydrogen o Emitting light from the atom is quantized (comes in discrete amounts)
» The Bohr Model -
Electrons in atoms can only occupy certain energy levels (orbits) – ground state When an electron moves between energy levels, energy is absorbed or emitted This energy corresponds to light of a specific energy/frequency The maximum number of electrons in an orbit depends on the size of the orbit Page 4 of 45
» Ions -
-
-
Neutral atoms have the same number of electrons as protons Atoms can gain or lose electrons to form ions, which are charged o Gain of electrons gives an anion o Loss of electrons gives a cation More than one electron can be gained or lost but >3 electrons is uncommon Charge is written at the top right and the sign comes after the number o O ! O2o N ! N3Ions form to obtain a Noble Gas configuration
» Noble Gases -
Group VIII (last column) on the periodic table 8 electrons in the outermost shell (2 for He) Stable electronic structure Do not gain/lose electrons Occur as isolated atoms
» Predicting Ion Formation -
Atoms gain or lose electrons to become isoelectronic as the nearest Noble gas Non-metals tend to form anions Metals tend to form cations
Lithium, a metal, loses an electron to become isoelectronic with helium
Oxygen, a non-metal, gains two electrons to become isoelectronic with neon
» Ionic Bonding -
An ionic bond is the electrostatic attraction between oppositely charged ions Ionic bonding results in a solid, crystal structured salts
Page 5 of 45
All matter consists of atoms – chemically indivisible particles of an element that cannot be created or destroyed Atoms of one element cannot be converted into atoms of another element Atoms of an element are identical and are different from atoms of any other element
» Matter -
Mixture (heterogeneous or homogenous) Pure substance (homogeneous) o Elements (contains atoms of only one type, refer to period table) o Molecules (2 or more atoms) o Compounds (2 or more elements combined in a unique ratio)
» Elements in Nature -
-
Noble Gases occur naturally as atoms: He, Ne, Ar, Kr, Xe, Rn Diatomic molecules: H2, N2, F2, O2, I2, Cl2, Br2 (Have No Fear Of Ice Cold Beer) Larger molecules: S8 Infinite aggregates: C, Cu, Fe, Ag
» Chemical Symbols -
One or two letters (1st is uppercase, 2nd is lowercase) E.g. C for carbon, Ca for calcium, Fe for iron (ferrum)
» Chemical Formulas -
Represent the atoms present E.g. methane is CH4, ammonia is NH3
Methane
Ammonia
» Chemical Equations -
Represent a change of one substance to another Word equation: methane + oxygen ! carbon dioxide + water Symbolic equation: CH4 + 2 O2 ! CO2 + 2 H2O
» States of Matter -
Different physical ways of packing particles A physical change is associated with a change of state A chemical change involves changing one substance into another
Page 1 of 45
» Physical v Chemical Change -
-
Physical change = substance alters its physical form but NOT its composition o Compound doesn’t change o Chemical bonds do not form or break o E.g. boiling water, freezing wax Chemical change = substance(s) is converted into a new substance(s) o Compound/allotrope changes o Chemical bonds form or break o E.g. burning of H2 with O2 to give H2O, reacting zinc with hydrochloric acid
» Physical Properties -
-
Properties that a substance shows by itself without changing or interacting with another substance o Colour o Melting point o Conductivity o Density o Surface tension Characteristics which belong to the substance itself, therefore, will always have that property
» Chemical Properties -
Properties of a substance that result in the formation of a new substance o Flammability o Corrosiveness o Reactivity with acid
» Properties of Matter -
An intensive property is independent of the amount of substance present e.g. pH An extensive property depends on the amount of substance present e.g. volume Page 2 of 45
» Atomic Structure -
Atoms are mostly empty space occupied by electrons All the positive charge and essentially all the mass lies in the centre – the nucleus The nucleus contains positively charge particles, protons, and uncharged neutrons Particle
Symbol
Proton Neutron Electron
Relative mass
Relative charge
p or p
+
1
+
n or n
0
1
0
-
1/1836
-
e or e
» Elements -
What determines element type? The number of protons in the nucleus of the atoms This is the atomic number, Z Atomic number gives the charge of the nucleus
» Atomic Symbol -
-
Atomic symbol, X, is uniquely related to the number of protons (atomic number, Z) o 2 protons (Z = 2) = helium = He o 8 protons (Z = 8) = oxygen = O o 92 protons (Z = 92) = uranium = U Atoms have no overall charge so atomic number = number of electrons
» Forces in Atoms -
Nucleons held together by the Strong Nuclear Force o Effective over short distances o Overcomes the repulsion between protons
» Cations and Anions -
-
Atoms can gain electrons to form anions o F + e- ! Fo O + 2e- ! O2o N + 3e- ! N3Atoms can lose electrons to form cations o Na ! Na+ + eo Mg ! Mg2+ + 2eo Al ! Al3+ + 3e-
Anion = a negative ion In ‘cation,’ the t looks like a plus (+)
» Electron Structures -
Group: number of electrons in outer shell/orbit Period: number of electron shells/orbits containing electrons Page 3 of 45
» Electromagnetic Radiation
-
Wavelength, λ, lambda o The distance between two adjacent identical points of the wave Frequency, ν, nu o The number of wave crests passing a given point per unit time All light waves travel at the same speed – the speed of light, c, is a constant
-
C = 2.998 x 108 ms-1 Wavelength and frequency are related to the speed of light
-
-
-
C = λν Radiation may have the same speed but the energy can vary Higher frequency means more rapidly oscillating waves which means higher energy Energy = Planck’s constant x frequency E = hv h = 6.626 x 10-34 Js
» Atomic Spectra -
-
When supplied with energy, an atom emits electromagnetic radiation of distinct frequencies, unique to that element – atomic emission spectrum Light emitted from a hydrogen lamp has only a few lines o Only light of certain energies is emitted o The pattern of lines is unique to hydrogen o Emitting light from the atom is quantized (comes in discrete amounts)
» The Bohr Model -
Electrons in atoms can only occupy certain energy levels (orbits) – ground state When an electron moves between energy levels, energy is absorbed or emitted This energy corresponds to light of a specific energy/frequency The maximum number of electrons in an orbit depends on the size of the orbit Page 4 of 45
» Ions -
-
-
Neutral atoms have the same number of electrons as protons Atoms can gain or lose electrons to form ions, which are charged o Gain of electrons gives an anion o Loss of electrons gives a cation More than one electron can be gained or lost but >3 electrons is uncommon Charge is written at the top right and the sign comes after the number o O ! O2o N ! N3Ions form to obtain a Noble Gas configuration
» Noble Gases -
Group VIII (last column) on the periodic table 8 electrons in the outermost shell (2 for He) Stable electronic structure Do not gain/lose electrons Occur as isolated atoms
» Predicting Ion Formation -
Atoms gain or lose electrons to become isoelectronic as the nearest Noble gas Non-metals tend to form anions Metals tend to form cations
Lithium, a metal, loses an electron to become isoelectronic with helium
Oxygen, a non-metal, gains two electrons to become isoelectronic with neon
» Ionic Bonding -
An ionic bond is the electrostatic attraction between oppositely charged ions Ionic bonding results in a solid, crystal structured salts
Page 5 of 45
