Flashcards in Module 2: Chapter 5 (Electrons and Bonding) Deck (23)
How many electrons can fit in the first four main shells?
1 = 2
2 = 8
3 = 18
4 = 32
Name the sub-shells in the first four shells
1 = 1s -> 2e-
2 = 2s -> 2e-
2p -> 6e-
3 = 3s -> 2e-
3p -> 6e-
3d -> 10e-
4 = 4s -> 2e-
4p -> 6e-
4d -> 10e-
4f -> 14 e-
What is a 'main shell' also referred to as?
principal quantum number, n
What is the electronic configuration order of subshells?
In order of increasing energy...
How is a shorthand version of configuration made?
Giving the previous noble gas in the periodic table, plus the remaining outer shell electrons
How is electron configuration constructed for ions?
'last in-first out'
exception of 4s, so 4s empties before 3d, as it has a slightly lower energy level
What are the different blocks of the periodic table?
- Hydrogen and Groups 1+2 are s-block
- Transition metals are d-block
- Groups 3-8(0) are p-block
- Extra are f-block
What is an atomic orbital?
An orbital describes the region of space where there is a high probability of finding an electron
How many electrons are in each orbital?
each orbital can only hold 2 electrons
How do electrons behave in orbitals?
Electrons in the same orbital have to have opposite spins
- as far as possible electrons in the same sub-shell prefer to be in separate orbitals to minimize repulsion
Describe a s-orbital
- electron cloud is within the shape of a sphere
- the greater the shell number n, the greater the number of its s-orbital
Describe a p-orbital
- electron cloud is within the shape of a dumb-bell
- the three separate p-orbitals are at right angles to each other
- the greater the shell number n, the further the p-orbital from the nucleus
What is an ionic bond?
the electrostatic attraction between positively and negatively charged ions
What do dot and cross diagrams show?
used to distinguish where the electrons originally came from
Describe the structure of ionic compounds
- in the compound every ion attracts oppositely charged ions in all directions
- the result is a giant ionic lattice
What are the properties of ionic compounds?
- in general the physical properties of a substance are always explained by consideration of structure and bonding
- generally most compounds have a high mp/bp (solid at room temp)
- due to the very strong electrostatic attraction between oppositely charged ions, lots of energy is needed to break the lattice
Describe the electrical conductivity of ionic compounds
- solid ionic compound will no conduct electricity as the ions can't move and carry charge, in fixed positions in the lattice
- only carry charge unless molten or dissolved
Describe solubility of ionic compounds
- often *not always* soluble in water, tend to be insoluble in most other solvents
- water is polar
- in a solution an ion can attract many water molecules
- the compound will tend to be soluble if the attractions formed compensate for those broken down when the lattice breaks down
- it is a fine balance, making predictions about solubility difficult
What is a covalent bond?
covalent bonding is electrostatic attraction between shared pair of electrons and the nuclei of the two bonded atoms
Describe a covalent bond
- a covalent bond is formed by the overlap of atomic orbitals
- in a covalent bond the attraction is localised, this is in contrast to ions which can attract in all directions
How many bonds does carbon, hydrogen, nitrogen and oxygen form?
4, 1, 3, 2
How many orbitals does each subshell have?
- an s subshell has 1 orbital
- p has 3 orbitals
- d has 5 orbitals
- f has 7 orbitals