Chemistry Module 2 - Chapter 5 Flashcards
What are shells?
In an atom, electron shells make up a model that helps us to visualise something that cannot be seen.
1. Shells are regarded as energy levels.
2. The energy increases as the shell number increases.
3. The shell number or energy level is called the principal quantum number n.
What is an atomic orbital?
An atomic orbital is a region around the nucleus that can hold up to two electrons, with opposite spins.
How many electrons can be found in the 1st shell?
2
How many electrons can be found in the 2nd shell?
8
How many electrons can be found in the 3rd shell?
18
How many electrons can be found in the 4th shell?
32
What subshells can the second shell be split into?
2s = contains 2 electrons slightly harder to remove
2p = containing 6 electrons slightly easier to remove.
What are the 4 types of sub-shells?
S
P
D
F
How many orbitals do the 4 subshells (S,P,D,F) contain?
S = 1
P = 3
D = 5
F = 7
How many electrons can an orbital hold?
It can hold 2 in each orbital
How many max electrons doe the four subshells (S,P,D,F) contain?
S = 2
P = 6
D = 10
F = 14
What does the s-orbital look like?
O (spherical shape)
What does the p-orbital look like?
8 (dumbbell shape)
What is the order in which the subshells full up?
1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p
From which shell onwards is S orbital present?
n = 1
From which shell onwards is P orbital present?
n = 2
From which shell onwards is D orbital present?
n = 3
From which shell onwards is F orbital present?
n = 4
What is the filling order in the n=2 shell?
2s, 2p
What is the filling order in the n=3 shell?
3s, 3p, 3d
What is the filling order in the n=4 shell?
4s, 4p, 4d, 4f
What is the Aufbau Principle?
Electrons always occupy the lowest energy sub-levels first.
Why does the 4s orbital fill before the 3d orbital?
4s orbital has a lower energy than 3d before it is filled.
How is the noble gas notation for an atom or ion deduced?
- The symbol of the noble gas from the previous period is written in square brackets.
- This represents the electronic structure of the noble gas.
- The rest of the electronic structure is written next to it.
What are the 3 main types of chemical bonds?
- Ionic
- Covalent
- Metallic
What is ionic bonding?
Ionic bonding is the electrostatic attraction between positive and negative ions. It holds together cations (positive ions) and anions (negative ions) in ionic compounds.
Give an example of an ionically bonded substance.
NaCl (Sodium Chloride - salt)
How are ions found in ionic compounds? What does this form?
Although it is convenient to look at ionic bonding acting between a small number of ions, each ion attracts oppositely charged ions in all directions.
The result is a giant ionic lattice structure containing billions of billions of ions.
Define covalent bonding.
Attraction between a shared pair of electrons and the nuclei.
Define metallic bonding.
Electrostatic attraction between the positive metal ions and the sea of delocalised electrons.
Electrons in which shell are represented in a dot and cross diagram?
The outer shell.
Why does giant ionic lattices conduct electricity when liquid but not when solid?
In a solid state, the ions are in fixed positions and thus cannot move. When they are in a liquid state the ions are mobile and thus can freely carry the charge.
Do Giant IOnic lattices have a high or low melting and boiling point?
They have a high melting and boiling point because a larger amount of energy is required to overcome the electrostatic bonds.