Chapter 5 - Electrons and bonding Flashcards
Where are shells with the highest energy levels located?
Further from the nucleus
What are the four types of sub-shells?
S-orbital
P-orbital
D-orbital
F-orbital
How many orbitals are there in an S sub-shell?
1
How many electrons can fit in the S sub-shell?
2
How many orbitals are there in the P sub-shell?
3
How many electrons are can fit in the P sub-shell?
6
How many orbitals are there in the D sub-shell?
5
How many electrons can fit in the D sub-shell?
10
How many orbitals are there in the F sub-shell?
7
How many electrons can fit in the F sub-shell?
14
What is an orbital?
An area of space that an electron moves in
What is spin-pairing?
When there are two electrons in an orbital, they must spin in opposite directions
What is the shape of S orbitals?
Spherical
What is the shape of P orbitals?
Dumbbell
How many P orbitals are there?
3
What is sub shell notation?
You write the energy shell, then sub-shell, then the number of electrons, e.g. 1s2 2s2 2p6
How to show electron configuration using the electrons in boxes method?
Each box represents one orbital and each arrow represents one electron
One arrow must go up and the other down
What is important to remember about the 4s sub-shell?
It is at a lower energy level than the 3d sub-shell, so will fill first but also empties first
We also write the 3d sub-shell first
In what manner will electrons fill orbitals with the same energy level?
Singly
What is an ionic bond?
An eletrostatic attraction between two oppositely charged ions
How can you work out the formula of an ionic compound?
Work out the charges on the ions and ensure it is balanced so the total charge is zero
What is n electronic orbital?
A region around the nucleus that can hold up to two electrons
What is a sub-shell?
Orbitals of the same type are grouped together
What is important to remember about two electrons in the same orbital?
They must have opposite spins
Why does the 4s shell fill before the 3d sub-shell?
It is at a lower energy level
What is shorthand notation for electronic structure?
You write the symbol of the previous noble gas plus the outer electron sub-shells
What are the three blocks of the periodic table?
S-block
P-block
D-block
Where is the S-block?
The first two groups of the periodic table
Where is the P-block?
The 6 groups on the right
Where is the D-block?
The central 10 groups
What does the block an element is in represent?
The highest energy electrons will be in that sub-shell
What do dot and cross diagrams show?
The arrangement of electrons in an atom
How to draw a dot and cross diagram?
Draw the outer shell of electrons inside a square bracket, using dots and crosses to show where the electrons came from. The charge should be indicated outside the bracket
Example of a giant ionic lattice
Sodium chloride
Why does sodium chloride have a high melting point?
It has very strong ionic bonds
3 characteristics of ionic compounds
They can conduct electricity when molten but not solid
High melting and boiling points
Tend to dissolve in water
Why can ionic compounds only conduct electricity when molten or dissolved?
In a solid, the ions are fixed in position by the ionic bonds, but when molten are mobile and can carry a charge
Why do ionic compounds have high melting and boiling points?
A lot of energy is needed to overcome the strong electrostatic forces
When will the melting point of an ionic lattice be higher?
For ions with greater charges, e.g. Ca 2+
Why do ionic compounds tend to dissolve in water?
Water is a polar solvent, so the charged ends of the water molecule are attracted to the charged ions and pull the ions from the lattice, causing it to dissolve
What does the solubility of an ionic compound depend upon?
The attractions within the lattice and the attraction between the ions and water molecules
What is a covalent bond?
The strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms
What happens when two atoms bond covalently?
Orbital overlap occurs
How to represent covalent bonds
Dot and cross diagrams with their outer orbitals overlapping
What is the displayed formula?
It shows how the relative positioning of atoms and the bonds between them
Give to exceptions to the octet rule
Boron trifluoride
Sulfur hexafluoride
Why is boron trifluoride an exception?
Boron only has 6 outer electrons, not 8
Why is sulfur hexafluoride an exception?
Sulfur has 12 electrons in its outer shell
What are multiple covalent bonds?
When two atoms share more than one pair of electrons
The best example of a double covalent bond
Oxygen, O2
What is a double covalent bond?
When two atoms share two pairs of electrons
The best example of a triple bond
Nitrogen, N2
What is a triple bond?
The electrostatic attraction between three shared pairs of atoms and the nuclei of the bonded atoms
What is special about CO2?
It has two double bonds
What are dative covalent bonds?
Where both electrons come from one atom
The best example of a dative covalent bond
NH3 and H+
How do you know when to use a dative bond?
Draw the dot and cross diagram of the two components
Where there are two spare electrons on one atom, this becomes the dative bond
