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1-Atomic Structure and the
Periodic Table
Relative Atomic Mass
The Nuclear Atom
Mass Spectrometry
Mass Spectrum
Molecular Mass from Mass Spectra
RAM from Mass Spectrometers
Electron Configuration
Evidence for Electron Configuration
Atomic Orbitals
Filling Orbitals
List Notation
Ionisation Energy
Explaining Patterns in Ionisation Energies
First Ionisation Energies
Successive Ionisation Energies
Periodicity
Melting Temperatures
Valency
Atomic Radius
Trends across a Period
1-Atomic Structure and the Periodic Table 1
, Trends in a Group
Size of Positive Ions
Size of Negative Ions
Electron Affinity
Relative Atomic Mass
The atoms of each type of element have a Relative Atomic Mass (RAM or Ar).
What is Relative Atomic Mass?
The average mass of one atom compared to one twelfth of the mass of one
atom of carbon-12.
The RAM takes account of the abundances of the different isotopes.
Ar = Average mass of an atom / 1/12th mass of 1 atom of 12 C
E.g. Magnesium exists as 3 isotopes: 24-mg (78.6%), 25-mg (10.11%) and 26-
mg (11.29%).
24x78.6/100 + 25x10.11/100 + 26x11.29/100 = 24.33 RAM has no units.
What is Relative Molecular Mass?
The ratio of the average mass of one molecule of an element or compound to one
twelfth of the mass of an atom of carbon-12.
The element Carbon is the atom that the mass of all other atoms is compared to -
Carbon has a RAM of 12.
The lightest atom is hydrogen - it has 1/12 the mass of carbon and so has a RAM of
1. Magnesium is twice as heavy as carbon - it has a RAM of 24.
Atoms are made from even smaller particles (subatomic particles):
Protons, Neutrons and Electrons.
Where are Protons, Neutrons and Electrons located?
Protons and Neutrons exist in a dense core at the centre of an atom - the
Nucleus.
The Electrons are spread out around the edge of the atom. They orbit the nucleus
in layers - Shells.
1-Atomic Structure and the Periodic Table 2
, 2 Important properties of Subatomic particles:
Mass and Charge.
The atoms of any element always contain the same number of protons - hydrogen
atoms always contain 1 proton and carbon atoms always contain 6 protons.
What is the number of protons in an atom known as?
The Atomic Number or Proton Number - the smaller number shown on the
periodic table.
What is the sum of protons and neutrons in an atom's nucleus known as?
The Mass Number - the larger number shown in the periodic table.
Mass Number = Number of Protons + Number of Neutrons
Number of Neutrons = Mass Number - Atomic Number (No.
Protons)
1-Atomic Structure and the Periodic Table 3
, The Nuclear Atom
What are Atoms?
The smallest uncharged particles into which an element can be divided and still
remain their characteristic properties.
What is the Nucleus?
The tiny, dense, positively charged centre of an atom composed of protons and
neutrons.
What is a Proton?
A positively charged subatomic particle found in the nucleus.
What is a Neutron?
A subatomic particle found in the nucleus which has zero charge and (nearly) the
same mass as the proton.
What is an Electron?
A negatively charged subatomic particle is about 1/1836 of the mass of a proton.
In neutral atoms, the number of electrons = the number of protons. It is only the
outer (valence shell) electrons that take part in bonding and in chemical reactions.
An atom contains a small, central, positively charged nucleus.
The diameter of the nucleus is about 1/10000 that of the atom.
Almost all the mass of an atom is concentrated in the nucleus.
Electrons orbit the nucleus.
What is an Isotope?
Atoms which contain the same number of protons but different numbers of
neutrons.
Isotopes of the same element have the same chemical properties as they all have
the same electron configurations.
What is the Atomic Number?
The number of protons in the nucleus of the atom.
The same number as the proton number.
1-Atomic Structure and the Periodic Table 4
, What is the Mass Number?
The number of protons + the number of neutrons.
What is the Relative Isotopic Mass?
Relative isotopic mass is the mass of an atom of an isotope of an element relative
to 1/12th the atomic mass of an atom of carbon-12.
Mass Spectrometry
What is a Mass Spectrometer used for?
To measure the masses of atoms, molecules and fragments of molecules.
What are the 4 stages of Mass Spectrometry?
Ionisation
Acceleration
Deflection
Detection
IADD
1-Atomic Structure and the Periodic Table 5
1-Atomic Structure and the
Periodic Table
Relative Atomic Mass
The Nuclear Atom
Mass Spectrometry
Mass Spectrum
Molecular Mass from Mass Spectra
RAM from Mass Spectrometers
Electron Configuration
Evidence for Electron Configuration
Atomic Orbitals
Filling Orbitals
List Notation
Ionisation Energy
Explaining Patterns in Ionisation Energies
First Ionisation Energies
Successive Ionisation Energies
Periodicity
Melting Temperatures
Valency
Atomic Radius
Trends across a Period
1-Atomic Structure and the Periodic Table 1
, Trends in a Group
Size of Positive Ions
Size of Negative Ions
Electron Affinity
Relative Atomic Mass
The atoms of each type of element have a Relative Atomic Mass (RAM or Ar).
What is Relative Atomic Mass?
The average mass of one atom compared to one twelfth of the mass of one
atom of carbon-12.
The RAM takes account of the abundances of the different isotopes.
Ar = Average mass of an atom / 1/12th mass of 1 atom of 12 C
E.g. Magnesium exists as 3 isotopes: 24-mg (78.6%), 25-mg (10.11%) and 26-
mg (11.29%).
24x78.6/100 + 25x10.11/100 + 26x11.29/100 = 24.33 RAM has no units.
What is Relative Molecular Mass?
The ratio of the average mass of one molecule of an element or compound to one
twelfth of the mass of an atom of carbon-12.
The element Carbon is the atom that the mass of all other atoms is compared to -
Carbon has a RAM of 12.
The lightest atom is hydrogen - it has 1/12 the mass of carbon and so has a RAM of
1. Magnesium is twice as heavy as carbon - it has a RAM of 24.
Atoms are made from even smaller particles (subatomic particles):
Protons, Neutrons and Electrons.
Where are Protons, Neutrons and Electrons located?
Protons and Neutrons exist in a dense core at the centre of an atom - the
Nucleus.
The Electrons are spread out around the edge of the atom. They orbit the nucleus
in layers - Shells.
1-Atomic Structure and the Periodic Table 2
, 2 Important properties of Subatomic particles:
Mass and Charge.
The atoms of any element always contain the same number of protons - hydrogen
atoms always contain 1 proton and carbon atoms always contain 6 protons.
What is the number of protons in an atom known as?
The Atomic Number or Proton Number - the smaller number shown on the
periodic table.
What is the sum of protons and neutrons in an atom's nucleus known as?
The Mass Number - the larger number shown in the periodic table.
Mass Number = Number of Protons + Number of Neutrons
Number of Neutrons = Mass Number - Atomic Number (No.
Protons)
1-Atomic Structure and the Periodic Table 3
, The Nuclear Atom
What are Atoms?
The smallest uncharged particles into which an element can be divided and still
remain their characteristic properties.
What is the Nucleus?
The tiny, dense, positively charged centre of an atom composed of protons and
neutrons.
What is a Proton?
A positively charged subatomic particle found in the nucleus.
What is a Neutron?
A subatomic particle found in the nucleus which has zero charge and (nearly) the
same mass as the proton.
What is an Electron?
A negatively charged subatomic particle is about 1/1836 of the mass of a proton.
In neutral atoms, the number of electrons = the number of protons. It is only the
outer (valence shell) electrons that take part in bonding and in chemical reactions.
An atom contains a small, central, positively charged nucleus.
The diameter of the nucleus is about 1/10000 that of the atom.
Almost all the mass of an atom is concentrated in the nucleus.
Electrons orbit the nucleus.
What is an Isotope?
Atoms which contain the same number of protons but different numbers of
neutrons.
Isotopes of the same element have the same chemical properties as they all have
the same electron configurations.
What is the Atomic Number?
The number of protons in the nucleus of the atom.
The same number as the proton number.
1-Atomic Structure and the Periodic Table 4
, What is the Mass Number?
The number of protons + the number of neutrons.
What is the Relative Isotopic Mass?
Relative isotopic mass is the mass of an atom of an isotope of an element relative
to 1/12th the atomic mass of an atom of carbon-12.
Mass Spectrometry
What is a Mass Spectrometer used for?
To measure the masses of atoms, molecules and fragments of molecules.
What are the 4 stages of Mass Spectrometry?
Ionisation
Acceleration
Deflection
Detection
IADD
1-Atomic Structure and the Periodic Table 5
