ELECTRONS AND BONDING Flashcards
What are shells?
Shells are regarded as energy levels, the energy increases as the shell number increases.
What is an atomic orbital?
An atomic orbital is a region around the nucleus that can hold up to two electrons of opposite spins.
How many sub-shells are there and how many electrons can fit in one shell?
1 = 2 2 = 8 3 = 18 4 = 32
What are the four different types of orbitals?
s-, p-, d- and f-
What shape is an s-orbital and how many electrons can it fit?
It has a spherical shape and it can fit two electrons.
What shape is a p-orbital and how many electrons can it fit?
A p-orbital has a dumbell shape (hourglass) and it has three seperate p-orbitals at right angles to each other: px, py, pz. Each p-orbital can contain up to 2 electrons and therefore 6 electrons in total. P-orbitals have 3 sub-shells.
How many electrons can fit in a d-orbital?
10
How many electrons fit into each orbital?
s = 2 p = 6 d = 10 f= 14
What is unusual in the filling of orbitals?
4s goes before 3d because 3d has more energy than 4s.
Why does an orbital have to have opposite spins?
Because electrons are negatively charged and repel one another and so need to have opposite directions (up and down). The opposite spins help to counteract the repulsion between electrons.
How are orbitals occupied in a sub-shell?
They are occupied singly first to avoid any repulsion.
What is the equation for the reaction between aluminium and fluorine?
2AL + 3F2 -> 2AlF3
What is an ionic lattice?
A repeating pattern of oppositely charged ions.
What is meant by the term covalent bonds?
A shared pair of electrons
Do metals conduct electricity when molten or solid?
Both because they have delocalised electrons.
What is ionic bonding?
The electrostatic attraction between oppositely charged ions.
What is covalent bonding?
Covalent bonding is the strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atom. This is within non-metals.
Do ionic bonds conduct electricity when solid or molten?
They conduct electricity when molten because they have mobile ions. They don’t conduct electricity when solid because they have ions in fixed positions and in an ionic lattice.
Do covalent bonds conduct electricity when molten or solid?
No because they have no mobile charge carriers.
What is the trend in group 3 (attraction between the nuclei and outermost electrons)?
The attraction between the nuclei and outermost electrons increases, the atomic radius decreases and the number of protons increases.
What are London forces used to describe?
Induced dipole-dipole interactions
What are Van der waals forces used to describe?
induced and permanent dipole interactions
What are dipole-dipole interactions?
Attractive forces between the positive end of one polar molecule and the negative end of another polar molecule.
What is the difference between induced and permanent dipole-dipole interactions?
Induced dipole-dipole interactions happen within all molecules whereas permanent only occurs in polar molecules.
