Periodic Trends / Electron Configurations
What is the electron configuration of cromium
1s2 2s2 2p6 3s2 3p6 4s1 3d5
3-amino propanal
Define first ionisation energy
The minimum amount of energy required to remove one valence electron from every atom in a mole of atoms in their gaseous state
Identify the chiral carbon and explain why it is chiral
CH3CH(OH)CH2CH3
Carbon 2. It has 4 different groups attached (-CH3, -H, -OH, -CH2CH3)
Rank Al, B, F and Na from the smallest to the largest electronegativity
Na < Al < B , F
Give the products of the hydrolysis of N-ethyl ethanamide CH3-CH2-NH-CO-CH3 in acidic and basic conditions
Acids: CH3-CH2-NH3+ and CH3-COOH
Basic: CH3-CH2-NH2 and CH3-COO-
Explain why atomic radius decreased from left to right across Period 2
Nuclear charge increases as the number of protons increase, while electrons are added to the same energy level. Shielding dose not increase so the strong nuclear charge results in a strong electrostatic force pulling electrons closer to the nucleus, decreasing atomic radius
An unknown organic molecule produces these observation
- It reacts with Fehling's solution forming a brick-red precipitate
- It reacts with sodium carbonate producing a gas
- It reacts rapidly with Lucas' Reagent turning cloudy
Identify the functional groups responsible for the observation
Reacts with Fehling's solution = Aldehyde
Reacts with sodium carbonate = Carboxylic Acid
Reacts rapidly with Lucas' Reagent = 3o Alcohol
Explain why Al has a lower first ionisation energy than Mg, even though it is further right in period 3
The first electron removed from Al is a 3p electron, whereas the first electron removed from Mg is a 3s electron. The 3p electron is higher in energy, further from the nucleus and more shielded from the. It is therefore easier to remove, giving Al a lower first ionisation energy than Mg.
CH3-CH=CH2 + HBr --> CH3-CH2-CH2-Br
CH3-CH2-CH2-Br + KOH(aq) --> CH3-CH2-CH2-OH
CH3-CH2-CH2-OH + Cr2O72-/H+ --> CH3-CH2-COOH
CH3-CH2-COOH + SOCl2 --> CH3-CH2-COCl