Chapter 5 - Electrons Bonding Flashcards
what are shells
energy levels
The shells are made up of atomic orbitals, which is a region around the nucleus that can hold up to 2 electrons, with opposite spins.
What is a atomic orbital
Modelled to be a region in space where there is a high probability of finding an electron.
s orbital
electron cloud is in the shape of a sphere
n= 1, 1 s orbital
p orbital
electron cloud is the shape of a dumbell
n=2, 3 p orbital
The greater the shell number, the further the p-orbital if from the nucleus.
D orbital
n=3, 5 d-orbital
f orbital
n= 4, 7 f-orbital
where is the highest energy electrons in the s-subshells
the first 2 groups
where is the highest energy electrons in d-subshells
the transition metals
where is the highest energy electrons in p-subshells
groups 3-8
why is the 4s sub shell before the 3d
because it has slightly less energy than 3d.
However, when it is filled up, the 3d energy levels fall below it.
this means that it fills up before the 3d and also empties before the 3d
What is the shorthand electron configuration
You use the last noble gases
useful for emphasising similarities in the outer shell’s electrons
What is ionic bonding
the electrostatic attraction between positive and negative ions.
Where does ionic bonding occur
It occurs between metal and non-metal ions
What is the structure of ionic compounds
A giant ionic lattice.
Properties of ionic bonds
High melting and boiling points
Soluble
Electrical conductivity
High melting and boiling points of ionic compounds
All ionic compounds are solid at RT, mainly because the electrostatic forces of attraction are too strong, and high temperatures are needed to overcome them.
The melting points are higher for lattices containing ions with higher ionic charges.
Solubility in ionic compounds
Many ionic compounds dissolve in polar solvents because the polar molecules break down the lattice and surround each ion in the solution.
However, this depends on the relative strengths of the attractions in the giant ionic lattice and the attractions between the water molecules and the ions.
Electrical conductivity in ionic compounds
In solid state, ionic compounds don’t conduct electricity, but they do when melted or dissolved in water. This is because when they are a solid, the ions are in a fixed position in the giant ionic lattice and there are no mobile charge carriers.
As a liquid, the solid ionic lattice breaks down and the ions are now free to move as mobile charge carriers.
Covalent Bonding
Strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms. It occurs between non-metallic elements and
polyatomic ions.
The Covalent Bond
It is the overlap of atomic orbitals, each containing an electron to share.
1 Difference between ionic and covalent bonding
Ionic attracts in all directions, but covalent attracts in only the shared pair of electron and the nuclei of the bonded atom.
What is a triple covalent bond
The electrostatic attraction is between 3 shared pairs of electrons and the nuclei of the bonding atoms.
A dative covalent bond
Or called a coordinate bond.
When the shared pair of electrons is supplied by one of the bonding atoms only. Originally, the pair was a lone pair.
Average bond enthalpy
The larger the value of the average bond enthalpy, the stronger the covalent bond.
What are the elements called around the dividing line
metalloids
Metallic bonding
Each solid atom has donated its negative outer-shell electrons to a pool of electrons.
What is metallic bonding
The electrostatic attraction between the cations and the delocalised electrons
What are the properties of metals
Strong metallic bonding
High electrical conductivity
High melting and boiling points
Don’t dissolve either
Giant covalent structures properties
Held by covalent bonds
High melting and boiling points
Insoluble (bonds too strong)
Non-conductors (except graphite and graphene)
Trends across period 2 and 3
Melting points increase from G1 to G4.
Sharp decrease from G14 to G15
Melting points are even lower from G15 to G18.
