Download The Periodic Table - Clydebank High School

The Periodic Table
• The periodic table is a list of all the
known elements arranged in Groups
and Periods
• All the elements on the LHS are metals
– RHS are non – metals.
• A Group is a vertical column.
• A Period is a row.
Groups
• The elements in the same group have similar
chemical properties.
• Group Names
• Group 1 - Alkali metals – very reactive
metals – stored in Oil.
• Group 7 – Halogens – very reactive non –
metals.
• Group 8 – The Noble Gases – very unreactive
non-metal gases.
• Transition metals – lie between groups 2 and
3.
Elements
• Elements are made up of only one type of
atom.
• Atoms are made up of tiny sub-atomic
particles:
• Protons, Electrons and Neutrons.
• The atom is in two parts a Core in the middle
– The Nucleus, and the Electron Clouds
which orbit the Nucleus.
The Structure of the Atom
The Nucleus contains Protons
and Neutrons.
Electrons are found in the
Electron clouds.
Protons: Mass =1 a.m.u, charge +
Electrons: Mass=1/1850 a.m.u, chargeNeutrons:Mass 1 a.m.u, charge 0.
Properties of Elements
• Every element has a unique number
called Atomic Number.
• The Atomic Number is the number of
Protons ( this is equal to the number of
electrons in a neutral atom)
• The Mass Number is a total of the
particles with mass i.e. protons and
neutrons.
Calculations!
• Number of Protons = Atomic Number.
• Number of Electrons= Number of protons.
• Number of neutrons = Mass number – Atomic
Number
• Example
• Chlorine – Mass No. = 35, Atomic No. = 17
• Number protons= 17, Number of electrons =
17, Number of Neutrons = 35-17 = 18.
Electrons
• Electrons are arranged inside the electron
clouds. These are inside “Energy Levels”
• The first energy level holds a maximum of 2
electrons within 1 cloud.
• The second energy level can hold up to 8
electrons – in pairs in 4 clouds
• The third energy level also hols 8 electrons in
4 clouds.
Electron Arrangement
• This is the name given to how the electrons
are organised.
• Example
• Sodium has 11 electrons. 2 will be in the first
energy level, 8 in the second energy level and
the one remaining electron will be in the third
energy level.
• The electron arrangement for Sodium is
written as 2,8,1.
Isotopes
• These are atoms of the same elements
that have different mass numbers i.e.
different numbers of neutrons.
• Example
• Chlorine – has 2 isotopes – one has a
mass of 35 a.m.u. the other has a mass
of 37 a.m.u.
Relative Atomic Mass( R.A.M. )
• This is the average mass of the isotopes –
taking into consideration their abundance. It
is usually not a whole number.
• Example
• Chlorine has a R.A.M. of 35.5
• It has 2 isotopes one with a mass of 35 the
other has a mass of 37.
• Therefore there must be more of the 35
isotope.