Atomic Structure And Bonding Flashcards
Element
Made up of only one type of atom
Compound
Contains more than one type of atom held together by bonds
Proton
+1
1
Nucleus
Neutron
0
1
Nucleus
Electron
-1
1/1836
Shells
Mass number
Protons and neutrons
Atomic number
Protons
Isotope
Atoms of the same element which have the same atomic number but a different mass number
Relative atomic mass
The average mass of an atom of an element compared to 1/12 of the mass of a carbon -12 atom
Ar
(Mass of atom 1 x%) + (mass of atom 2 x%)
Divided by
Total number of atoms
Noble gases
They are unreactive because they have full outer shells
Ionic bonding
Metal and non metal react
Metals form positive ions
Non metals form negative ions
Opposite charged ions are electrostatically attracted to each other
Giant lattice is formed
Covalent bonding
Atoms share a pair of electrons and the shared electrons are attracted to both nuclei
When can ionic compounds conduct electricity
Cannot conduct electricity when solid because ions are fixed
Can conduct electricity when in aqueous or molten solution because ions are free to move and carry charge
Why do ionic compounds have high melting and boiling points
They have strong electrostatic attraction between the ions and a lot of energy is required to break them apart
Why do simple covalent molecules have low melting and boiling points
They have weak intermolecular forces and not a lot of energy is needed to overcome these forces
Why do simple covalent molecules not conduct electricity
They have no charged particles free to move
Diamond
Giant covalent structure
Each carbon atom is bonded to 4 other carbon atoms
Tetrahedral shape
Why does diamond have a high melting and boiling point
It has many strong covalent bonds and a lot of energy is required to break these bonds
Why does diamond not conduct electricity
It has no free charged particles
Why is diamond very hard
It is a giant covalent lattice
What is diamond used for
Cutting tools
Jewellery
Graphite
Giant covalent structure
Each carbon atom is bonded to 3 other carbon atoms
Layers of hexagon
Why does graphite have a high melting and boiling point
It has many strong covalent bonds and lots of energy is needed to break these bonds
Why does graphite conduct electricity
The free delocalised electrons are free to move
Why is graphite quite soft
There are weak forces of attraction between layers of carbon atoms
What is graphite used for
Lubricant
Pencil
The free electrons allow the layers to slide over each other
C60 Fullerene
Simple molecule
Each carbon atoms is bonded to 3 other carbon atoms
Spherical molecule with 60 carbons
Why does C60 Fullerene have a low melting and boiling point
There are weak intermolecular forces so it does need much energy to break these forces
Why does C60 Fullerene not conduct electricity
The delocalised electrons have to stay within the molecule and cannot move from one molecule to the other
Metal definition
Strong electrostatic attraction between positive metal ions and a sea of delocalised electrons
Giant metallic lattice
Why do metals have a very high melting and boiling point
It is a giant lattice with strong electrostatic attraction between the positive metal ions and sea of delocalised electrons and a lot of energy is needed to break bonds and overcome forces
Why are metals malleable
The delocalised electrons allow the layers of metal ions to slide over each other
Alloy
Mixture or atleast 2 elements where one of these is a metal
