Alevel Chemistry Revision PC 02
Revision Material
Duration: 2nd – 8th March
Topic 2 Atomic Structure
This topic describes the type, number and distribution of the fundamental particles which make up an atom and the impact of this on some atomic properties.
Learning outcomes
Candidates should be able to:
2.1 Particles in the atom (a) identify and describe protons, neutrons and electrons in terms of their relative charges and
relative masses
(b) deduce the behaviour of beams of protons, neutrons and electrons in electric fields
(c) describe the distribution of mass and charge within an atom
(d) deduce the numbers of protons, neutrons and electrons present in both atoms and ions
given proton and nucleon numbers (atomic and mass numbers) and charge
2.2 The nucleus of the (a) describe the contribution of protons and neutrons to atomic nuclei in terms of proton (atomic)
atom number and nucleon (mass) number
(b) distinguish between isotopes on the basis of different numbers of neutrons present
x x
(c) recognise and use the symbolism y A for isotopes, where is the nucleon (mass) number
and y is the proton (atomic) number
2.3 electron: energy (a) describe the number and relative energies of the s, p and d orbitals for the principal quantum
levels, atomic orbitals, numbers 1, 2 and 3 and also the 4s and 4p orbitals
ionization energy, (b) describe and sketch the shapes of s and p orbitals
electron affinity (c) state the electronic configuration of atoms and ions given the proton (atomic) number and
charge, using the convention 1s2 2s2 2p6 , etc.
(d) (i) explain and use the term ionisation energy
(ii) explain the factors influencing the ionisation energies of elements
(iii) explain the trends in ionisation energies across a period and down a group of the
Periodic Table (see also Section 9.1)
(e) deduce the electronic configurations of elements from successive ionisation energy data
(f) interpret successive ionisation energy data of an element in terms of the position of that
element within the Periodic Table
, 2.1 Particles in the atom
(a) identify and describe protons, neutrons and electrons in terms of their relative charges and relative masses
sub-atomic particle relative mass relative charge
proton 1 +1
neutron 1 0
electron 1/1836 -1
Proton number is the number of protons in the nucleus of an atom
Nucleon number is the total number of protons and neutrons
(b) deduce the behaviour of beams of protons, neutrons and electrons in electric fields
Beams of protons, neutrons and electrons behave differently in an electric field due to their differing properties. The diagram shows the path of a
beam of electrons in an electric field. Add and label lines to represent the paths of beams of protons and neutrons in the same field.
When separate beams of electrons, neutrons or protons are passed through an electric field in the apparatus below, they behave differently.
Which of these three particles will be deflected the most by the electric field? Electrons
In which direction will this particle be deflected? Towards the positive pole
Explain your answer. Electron has negative charge and has very small mass
2.2 The nucleus of the atom
Isotopes atoms which have same proton number/atomic number [1] different mass number/nucleon number [1]
Chemical properties of isotopes are identical
MASS NUMBER & ATOMIC NUMBER
Atomic Number (Z) Number of protons in the nucleus of an atom
Mass Number (A) Sum of the protons and neutrons in the nucleus
Example
name of nucleon atomic number of number of number of overall
element number number protons neutrons electrons charge
lithium 6 3 3 3 2 +1
oxygen 17 8 8 9 10 -2
iron 54 26 26 28 24 +2
chlorine 35 17 17 18 17 0
atomic nucleon number of number of number of symbol
number number electrons protons neutrons
6
3 2 3
Li+
23 26 32
Revision Material
Duration: 2nd – 8th March
Topic 2 Atomic Structure
This topic describes the type, number and distribution of the fundamental particles which make up an atom and the impact of this on some atomic properties.
Learning outcomes
Candidates should be able to:
2.1 Particles in the atom (a) identify and describe protons, neutrons and electrons in terms of their relative charges and
relative masses
(b) deduce the behaviour of beams of protons, neutrons and electrons in electric fields
(c) describe the distribution of mass and charge within an atom
(d) deduce the numbers of protons, neutrons and electrons present in both atoms and ions
given proton and nucleon numbers (atomic and mass numbers) and charge
2.2 The nucleus of the (a) describe the contribution of protons and neutrons to atomic nuclei in terms of proton (atomic)
atom number and nucleon (mass) number
(b) distinguish between isotopes on the basis of different numbers of neutrons present
x x
(c) recognise and use the symbolism y A for isotopes, where is the nucleon (mass) number
and y is the proton (atomic) number
2.3 electron: energy (a) describe the number and relative energies of the s, p and d orbitals for the principal quantum
levels, atomic orbitals, numbers 1, 2 and 3 and also the 4s and 4p orbitals
ionization energy, (b) describe and sketch the shapes of s and p orbitals
electron affinity (c) state the electronic configuration of atoms and ions given the proton (atomic) number and
charge, using the convention 1s2 2s2 2p6 , etc.
(d) (i) explain and use the term ionisation energy
(ii) explain the factors influencing the ionisation energies of elements
(iii) explain the trends in ionisation energies across a period and down a group of the
Periodic Table (see also Section 9.1)
(e) deduce the electronic configurations of elements from successive ionisation energy data
(f) interpret successive ionisation energy data of an element in terms of the position of that
element within the Periodic Table
, 2.1 Particles in the atom
(a) identify and describe protons, neutrons and electrons in terms of their relative charges and relative masses
sub-atomic particle relative mass relative charge
proton 1 +1
neutron 1 0
electron 1/1836 -1
Proton number is the number of protons in the nucleus of an atom
Nucleon number is the total number of protons and neutrons
(b) deduce the behaviour of beams of protons, neutrons and electrons in electric fields
Beams of protons, neutrons and electrons behave differently in an electric field due to their differing properties. The diagram shows the path of a
beam of electrons in an electric field. Add and label lines to represent the paths of beams of protons and neutrons in the same field.
When separate beams of electrons, neutrons or protons are passed through an electric field in the apparatus below, they behave differently.
Which of these three particles will be deflected the most by the electric field? Electrons
In which direction will this particle be deflected? Towards the positive pole
Explain your answer. Electron has negative charge and has very small mass
2.2 The nucleus of the atom
Isotopes atoms which have same proton number/atomic number [1] different mass number/nucleon number [1]
Chemical properties of isotopes are identical
MASS NUMBER & ATOMIC NUMBER
Atomic Number (Z) Number of protons in the nucleus of an atom
Mass Number (A) Sum of the protons and neutrons in the nucleus
Example
name of nucleon atomic number of number of number of overall
element number number protons neutrons electrons charge
lithium 6 3 3 3 2 +1
oxygen 17 8 8 9 10 -2
iron 54 26 26 28 24 +2
chlorine 35 17 17 18 17 0
atomic nucleon number of number of number of symbol
number number electrons protons neutrons
6
3 2 3
Li+
23 26 32
