Ch5- Electrons and Bonding Flashcards
What is the expression used to calculate electrons in each shell?
2n2
What are the 4 sub-shells?
s p d f
How many electrons can an orbital contain?
2, with opposite spins.
What is an atomic orbital?
A region around nucleus where it is likely to find an electron.
What is the shape of the s-orbital?
How many s, p d and f orbitals are there?
s = 1 (2 electrons)
p = 3 (6 electrons)
f = 5 (10 electrons)
d = 7 (14 electrons)
What is the shape of the p orbitals?
Describe the filling of orbitals and the overlap of 2 energy levels:
There are 2 exceptions to the ‘aufbau’ principle. What are they and why do they behave this way?
Explain how you would use ‘electron-in-box’ method?
How does Shorthand Electron Configuration work and give an example using Potassium, K:
take the previous noble gas and put square brackets around it. Then add the rest of the orbitals if necessary.
E.g. Potassium, Atomic number 19:
Normal e.c. : 1s2 2s2 2p6 3s2 3p6 4s1
Shorthand: [Ar] 4s1
E.g. Ar, Atomic number 18:
Shorthand = [Ne] 3s23p6
Which groups cover:
- the s-block
- the p-block
- the d-block
S-block= Groups 1-2
P-block= Groups 13-18
D-block= Groups 3-12
Why do d-block (transition metals) form + ions and lose e- ?
D-block form + ions, they lose e- from 4s sub shell before 3d sub shell. This is because 4s sub shell fills before 3d sub shell, once 3d filled up, 3d sub shell falls to a lower energy level than 4s sub shell.
In an ionic compound, describe the solubility:
What is the definition of a covalent bond?
A covalent bond is the strong electrostatic attraction that form between the shared pair of electrons and the nuclei of the bonded atoms. A covalent bond form between non-metals. The attraction is ‘localised’ (unlike in ionic compounds, the attraction acts in all directions)
What is a dative covalent bond?
Dative CB are formed when the shared pair of electrons has been provided by only one of the bonding atoms. The shared pair was originally a lone pair of electrons on one the bonded atoms.
What is the octet rule?
The tendency of atoms to prefer to have eight electrons in the valence shell.
When atoms have fewer than eight electrons, they tend to react and form more stable compounds
What are exceptions to the octet rule?
Some elements that form a CB will not have a noble gas electron structure, i.e. they do not end up with 8 electrons in their outer shell.
E.g. Boron Triflouride, BF3
Boron only has 6 electrons in outer shell (3 of its own) and Flourine obeys the octet rule by having 8 in its outer shell (7 of its own)
E.g. SF6, sulfur hexaflouride (a hypervalent molecule)
Octahedrral structure, Flourine obeys octet rule whereas Sulfur has 12 electrons in outer shell.
