Atomic bonding involves what holds the material together. macrostructure 1-100 micro-cracks (biggest) microstructure 0.1-1 grain size nanostructure 1-100nm power size molecular 0.1-1nm atomic structure (smallest)
atom, the smallest unit of matter that retains the identity of the substance.
These components create the atom. The lines in a atom diagram display how the electrons orbit the atom.
An atom has 2 regions, the nucleus (the centre of the atom) the nucleus contains all the mass of the atom.
The electron could is the area around the nucleus, this has almost no mass but occupies the most space.
What is in the nucleus
-sub atomic particles
The electronic cloud around the nucleus contains electrons that are subatomic particles with a positive charge and almost no mass. (Visit blackboard for diagrams on mass and properties)
Electrons are arranged in energy levels or shells around the nucleus of an atom. 1 levels L(2 electrons) 2nd L(8 electrons) 3rd shell M(18 electrons) 4th shell N (32 electrons)
When the maximum amount of electrons are in a shell these materials are hard to alter they are unreactive and stable. These materials often are stable colour less and odourless.
The top number in an element is the mass number (superscript) and the bottom number is the atomic number (subscript)
Atomic number – the number of protons in the nucleus of each atom of that element (atomic number is equal to electrons)
Mass number – the number of protons and neutrons in the nucleus of an atom.
Atoms of the same elements can have different numbers of electrons – isotopes.
Carbon 12 has the names number of neutrons as carbon 14.
Allotropes – different structural forms of the same element, for example graphite and diamond
Element atomic bonds
Ionic bond- TRANSFER OF ELECTRONS FORM A METAL TO A NONMETAL
Metallic bonding – attractive force holding metals together
Covalent bond- results form sharing electrons between atoms (when two different atoms are sharing bonds (often in non metals) a result of chemical reactions.
Van der Waals bonding polar covalent bonding.
Electropositivity is the ability to donate an electrode so leaving a positive ion called a Cation.
Electronegativity- the ability to attract electrons creating a negative ions called an anion.
Valence is the number of electrons vacancies in the outer shell of an atom that participate in bonding or chemical reactions. For example if one atom occupies the outer shell it has a valence of 1 as it can be used to bond.
Ionic materials are often brittle but conductive.
Metallic bonds often involves a sea of electrons by using valence electrons.
REVISE ALL FORMS OF BONDING AND INSERT HERE (GCSE LEVEL)
Van der Waals bonding – electrons are shared but not equally. For example hydrogen, constraining oxygen which is more electronegative than hydrogen however they occupy the same space to create stability in the atom. These bonds are often weak, this is seen as it is easy to break waters bond simply boiling it can change the structure.
Atomic Arrangement and Crystal Structure
Inter atomic spacing, simple negative positive bonding. (VISIT BLACKBOARD for Newtons law of gravitations attraction. Insert here)
These atoms attract each other, however when too close the electrons in the atom will repel each other. Like with a spring the closer it gets the stronger the repulsive force.
the strength of a material is the force necessary to break the inter atomic bonds. A broken material is litrally breaking the atomic bonds. For example water takes no force to break, where as metals take significantly more force due to the