Unit 1
Physical Chemistry
, Section 1
Atomic Structure
, Atoms
• Elements are made up of atoms. In turn, atoms are made up of 3 types of sub-
atomic particles;
• Protons - (Charge = __ , Mass = _)
• Electrons - (Charge = __ , Mass = _)
• Neutrons - (Charge = __ , Mass = _)
• Protons and neutrons make up the nucleus, whilst electrons circle round the
nucleus in orbitals.
• Top number is the mass number (protons + neutrons), bottom number is
the atomic number (protons + electrons).
Taken from Seneca Learning
, Atoms
• Elements are made up of atoms. In turn, atoms are made up of 3 types of sub-
atomic particles;
• Protons - (Charge = +1 , Mass = 1)
• Electrons - (Charge = -1 , Mass = 1/2000)
• Neutrons - (Charge = 0 , Mass = 1)
• Protons and neutrons make up the nucleus, whilst electrons circle round the
nucleus in orbitals.
• Top number is the mass number (protons + neutrons), bottom number is
the atomic number (protons + electrons).
Taken from Seneca Learning
, Ions
• Ions are the product when atoms gain or lose electrons. Negative ions (anions)
have ____ electrons than protons, whilst positive ions (cations) have _____
electrons compared to protons.
• The different forms of these elements are known as Isotopes, which will have the
same number of protons but a different number of neutrons. Therefore, the
atomic number will ____ , but the mass number will _____.
• Properties of these isotopes; Physical properties depend on the mass of the atom
(will _____), Chemical properties depend on the electronic configuration (will
_____).
, Ions
• Ions are the product when atoms gain or lose electrons. Negative ions (anions)
have more electrons than protons, whilst positive ions (cations) have
less electrons compared to protons.
• The different forms of these elements are known as Isotopes, which will have the
same number of protons but a different number of neutrons. Therefore, the
atomic number will be the same, but the mass number will change.
• Properties of these isotopes; Physical properties depend on the mass of the atom
(will change), Chemical properties depend on the electronic configuration (will
remain the same).
, Questions
• 1) Work out how many protons, neutrons, and electrons Magnesium contains (Mass number = 24,
Atomic number = 12).
• 2) Work out how many protons, neutrons, and electrons Aluminium contains (Mass number = 27,
Atomic number = 13).
• 3) Work out the element in the periodic table which contains 8 protons, 8 electrons, and 8 neutrons.
• 4) Work out the element in the periodic table which contains 11 protons, 11 electrons and 12 neutrons.
• 5) Why do isotopes of the same element have similar chemical properties?
• 6) Name one physical property which will differ between isotopes of the same element?
• 7) Work out how many protons, neutrons, and electrons that Cl-35 and Cl-37 contains.
, Answers
• 1) Work out how many protons, neutrons, and electrons Magnesium contains (Mass number = 24, Atomic number
= 12).
• 2) Work out how many protons, neutrons, and electrons Aluminium contains (Mass number = 27, Atomic number
= 13).
• 3) Work out the element in the periodic table which contains 8 protons, 8 electrons, and 8 neutrons.
• 4) Work out the element in the periodic table which contains 11 protons, 11 electrons and 12 neutrons (see a
pattern?).
• 5) Why do isotopes of the same element have similar chemical properties?
• 6) Name one physical property which will differ between isotopes of the same element?
• 7) Work out how many protons, neutrons, and electrons that Cl-35 and Cl-37 contain.
• -
, Models of the Atom
• 1) JJ Thomson's Plum Pudding Model (start of 1900s) – Proposed that electrons
act as plums in a pudding of positive charge.
• 2) Rutherford or Nuclear model (1911) – Geiger, Marsden, and Rutherford fired
positive alpha particles at a gold sheet (Gold Foil experiment), to show that most
of the atom is empty space and there is a tiny positively charged nucleus in the
center of the atom.
• 3) Niels Bohr (1913) – Proposed that electrons are fixed in shells and orbit the
nucleus, where each shell has a fixed energy.
, Questions
Taken from Physics and Maths tutor Taken from Physics and Maths tutor
Physical Chemistry
, Section 1
Atomic Structure
, Atoms
• Elements are made up of atoms. In turn, atoms are made up of 3 types of sub-
atomic particles;
• Protons - (Charge = __ , Mass = _)
• Electrons - (Charge = __ , Mass = _)
• Neutrons - (Charge = __ , Mass = _)
• Protons and neutrons make up the nucleus, whilst electrons circle round the
nucleus in orbitals.
• Top number is the mass number (protons + neutrons), bottom number is
the atomic number (protons + electrons).
Taken from Seneca Learning
, Atoms
• Elements are made up of atoms. In turn, atoms are made up of 3 types of sub-
atomic particles;
• Protons - (Charge = +1 , Mass = 1)
• Electrons - (Charge = -1 , Mass = 1/2000)
• Neutrons - (Charge = 0 , Mass = 1)
• Protons and neutrons make up the nucleus, whilst electrons circle round the
nucleus in orbitals.
• Top number is the mass number (protons + neutrons), bottom number is
the atomic number (protons + electrons).
Taken from Seneca Learning
, Ions
• Ions are the product when atoms gain or lose electrons. Negative ions (anions)
have ____ electrons than protons, whilst positive ions (cations) have _____
electrons compared to protons.
• The different forms of these elements are known as Isotopes, which will have the
same number of protons but a different number of neutrons. Therefore, the
atomic number will ____ , but the mass number will _____.
• Properties of these isotopes; Physical properties depend on the mass of the atom
(will _____), Chemical properties depend on the electronic configuration (will
_____).
, Ions
• Ions are the product when atoms gain or lose electrons. Negative ions (anions)
have more electrons than protons, whilst positive ions (cations) have
less electrons compared to protons.
• The different forms of these elements are known as Isotopes, which will have the
same number of protons but a different number of neutrons. Therefore, the
atomic number will be the same, but the mass number will change.
• Properties of these isotopes; Physical properties depend on the mass of the atom
(will change), Chemical properties depend on the electronic configuration (will
remain the same).
, Questions
• 1) Work out how many protons, neutrons, and electrons Magnesium contains (Mass number = 24,
Atomic number = 12).
• 2) Work out how many protons, neutrons, and electrons Aluminium contains (Mass number = 27,
Atomic number = 13).
• 3) Work out the element in the periodic table which contains 8 protons, 8 electrons, and 8 neutrons.
• 4) Work out the element in the periodic table which contains 11 protons, 11 electrons and 12 neutrons.
• 5) Why do isotopes of the same element have similar chemical properties?
• 6) Name one physical property which will differ between isotopes of the same element?
• 7) Work out how many protons, neutrons, and electrons that Cl-35 and Cl-37 contains.
, Answers
• 1) Work out how many protons, neutrons, and electrons Magnesium contains (Mass number = 24, Atomic number
= 12).
• 2) Work out how many protons, neutrons, and electrons Aluminium contains (Mass number = 27, Atomic number
= 13).
• 3) Work out the element in the periodic table which contains 8 protons, 8 electrons, and 8 neutrons.
• 4) Work out the element in the periodic table which contains 11 protons, 11 electrons and 12 neutrons (see a
pattern?).
• 5) Why do isotopes of the same element have similar chemical properties?
• 6) Name one physical property which will differ between isotopes of the same element?
• 7) Work out how many protons, neutrons, and electrons that Cl-35 and Cl-37 contain.
• -
, Models of the Atom
• 1) JJ Thomson's Plum Pudding Model (start of 1900s) – Proposed that electrons
act as plums in a pudding of positive charge.
• 2) Rutherford or Nuclear model (1911) – Geiger, Marsden, and Rutherford fired
positive alpha particles at a gold sheet (Gold Foil experiment), to show that most
of the atom is empty space and there is a tiny positively charged nucleus in the
center of the atom.
• 3) Niels Bohr (1913) – Proposed that electrons are fixed in shells and orbit the
nucleus, where each shell has a fixed energy.
, Questions
Taken from Physics and Maths tutor Taken from Physics and Maths tutor
