2.2. Electrons, Structure and Bonding Flashcards
How many electrons can fill the first 4 shells?
n = 1 -> 2
n= 2 -> 8
n=3 -> 18
n=4 -> 32
‘n’ = principle quantum number, the shell/energy level number
What are atomic orbitals?
regions around the nucleus that can hold up 2 electrons, with opposite spins
The greater the shell number n, what happens to the s and p orbital?
Greater the radius of its s-orbital
Further the p orbital is from the nucleus
what is the shape of s orbitals?
Sphere
what are the shapes of p orbitals?
Dumbbells on y, x and z axis
How many electrons can fill the s, p, and d sub shells?
s = 2
p = 6
d = 10
What property do electrons have?
- SPIN, so they are shown as arrows. Any 2 electrons sharing an orbital will have opposite spins.
Write the electron configuration of krypton (36 e-)
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6
What is the shorthand configuration for krypton?
- You can use configurations of the nearest noble gases to make things easier, and then the rest of the sub shells + electrons after.
[Ar] 3d¹⁰ 4s² 4p⁶
What are the 2 exceptions?
Copper and chromium
They are more stable with half full sub shells, and so for chromium instead of 4s23d4, it is 4s13d5.
This is a similar case for copper too.
What should you be careful with when it comes to ions?
- Write out the configuration of the atom first, and then remove or add electrons to give the ion, so that the order of filling becomes correct.
- The 4s also EMPTIES before 3d.
E.g.
Ni (28) = [Ar] 3d⁸ 4s²
Ni2+ = [Ar] 3d⁸ because the 4s loses the 2 electrons.
What is ionic bonding?
strong electrostatic attraction between positive and negative ions
What is the structure of ionic compounds?
- GIANT ionic lattice
- Repeating pattern of ions where each ion attracts oppositely charged ions in all directions
What is a property of ionic compounds? 1. MP
Melting and boiling points: lots of energy to overcome strong electrostatic forces of attraction between oppositely charged ions in the giant ionic lattice.
What is a property of ionic compounds? 2. Solubility
Solubility: many dissolve in polar solvents. polar water molecules for example are attracted to the ions and bond to them, weakening ionic bonding and the ions become surrounded and break free, causing the lattice to break down. Ions w large charges = attraction may be too strong = not very soluble.
What is a property of ionic compounds? 3. Conductivity
Electrical conductivity: solid - doesnt conduct, ions are in fixed positions and so arent mobile. Aqueous/molten: ions are now free to move and carry charge.
what is a covalent bond?
strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms. Overlap of atomic orbitals, each containing one electron, to give a shared pair of electrons.