EXAM QUESTIONS - SPRING MOCK

Question 1

Suggest why the branched chain isomer shown above has a lower boiling point than octane [2 marks]

Answer 1

1. Less surface area [1]
2. So fewer/weaker/less Van der Waals forces [1]

Question 2

State two differences between the ‘plum pudding’ model and the model of the atomic structure used today [2 marks]

Answer 2

NUCLEAR MODEL:

1. (Central) nucleus contains protons and neutrons. [1]
2. Electrons are now arranged in energy levels/shells/orbitals [1]

Question 3

Table 1 shows come data about fundamental particles in an atom.

Proton mass: 1.6725 x 10⁻²⁴
Neutron mass: 1.6748 x 10⁻²⁴
Electron mass: 0.0009 x 10⁻²⁴

An atom of hydrogen can be represented as ¹H

Use data from Table 1 to calculate the mass of this hydrogen atom. [1 mark]

Answer 3

1.6734 × 10⁻²⁴ [1]

1.6725 x 10⁻²⁴ + 0.009 x 10⁻²⁴

¹H = 1 proton + 1 electron

Question 4

This question is about atomic structure.

The figure below is a model proposed by Rutherford to show the structure of an atom.

https://undsci.berkeley.edu/lessons/pdfs/rutherford.pdf

State two features of the current model that are not shown in the Rutherford model.

Answer 4

1. Current model includes: neutrons and protons [1]
2. Current model shows electrons in different energy levels/orbitals [1]

Question 5

Explain how permanent dipole-dipole forces arise between iodine mono chloride molecules. [2 marks]

Answer 5

Difference in electronegativity leads to bond polarity [1]

(Dipoles don’t cancel therefore the molecule has an overall permanent dipole) and there is an attraction between ∂+ on one molecule and ∂− on another [1]

Question 6

Write the full electron configuration for each of the following species.

Cl⁻

Fe²⁺

Answer 6

Cl⁻ = 1s²2s²2p⁶3s²3p⁶

Fe²⁺ = 1s²2s²2p⁶3s²3p⁶3d⁶

For Fe²⁺ it would seem like : 1s²2s²2p⁶3s²3p⁶4s²3d⁴ …
…but the 4s orbital is filled/removed first.

Question 7

Write an ionic equation, including state symbols, to represent the process that occurs when the third ionisation energy of manganese is measured. [1 mark]

Answer 7

Mn²⁺ (g) ――> Mn³⁺ (g) + e⁻

Question 8

Element R contains 7 electrons.

(a) Deduce the shorthand noble gas electron configuration of an atom of element R.

(b) Identify R and deduce the formula for the compound formed when R reacts with the Group 2 metal in the same period as R.

Answer 8

(a) [He] 2s²3p³

(b)
R = Nitrogen
Be₃N₂