EduNinja
[Maximum number: 1]

Two groups of students (Group A and Group B) carried out a project* on the chemistry of some group 7 elements (the halogens) and their compounds.

(a)

In this project the students explored several aspects of the chemistry of the halogens. In the original preparation of ICl⁡(1)\operatorname{ICl}(1), they observed the yellow-green colour of chlorine gas, Cl2( g)\mathrm{Cl}_{2}(\mathrm{~g}), reacting with solid iodine, I2( s)\mathrm{I}_{2}(\mathrm{~s}).

[ 1 ]
(i)

State the full electron configuration of iodine ( Z=53 ).

[ 1 ]
[Maximum number: 4]

Modern analytical techniques are used widely for different purposes in everyday life.

(a)

Two types of spectroscopy are absorption and emission. Distinguish between each type of spectra, including how each is produced.
Absorption spectra:
Emission spectra:

[ 4 ]
[Maximum number: 4]

Modern analytical techniques are used widely for different purposes in everyday life.

(a)

Two types of spectroscopy are absorption and emission. Distinguish between each type of spectra, including how each is produced.

Absorption spectra:

Emission spectra:

[ 4 ]
(a)

Describe the essential difference between the emission spectrum of sodium and the absorption spectrum of sodium.

[ 1 ]
[Maximum number: 2]

Electromagnetic waves can transfer energy and carry information.

(a)

State the relationship between the energy of a wave and its wavelength.

[ 1 ]
(b)

Identify the region of the electromagnetic spectrum that can be used to obtain the concentration of Cr3+\mathrm{Cr}^{3+} ions in industrial waste waters.

[ 1 ]
[Maximum number: 1]

Electromagnetic waves can transfer energy and carry information.

(a)

State the relationship between the energy of a wave and its wavelength.

[ 1 ]
[Maximum number: 2]

There are many oxides of silver with the formula AgxOy\mathrm{Ag}_{\mathrm{x}} \mathrm{O}_{\mathrm{y}}. All of them decompose into their elements when heated strongly.

(a)

Outline the model of electron configuration deduced from the hydrogen line emission spectrum (Bohr's model).

[ 2 ]
[Maximum number: 2]

There are many oxides of silver with the formula AgxOy.\mathrm{Ag}_{x} \mathrm{O}_{y^{.}}All of them decompose into their elements when heated strongly.

(a)

Outline the model of electron configuration deduced from the hydrogen line emission spectrum (Bohr's model).

[ 2 ]
[Maximum number: 1]

The equations show steps in the formation and decomposition of ozone in the stratosphere, some of which absorb ultraviolet light.

Step 1O2→2O⋅1 \quad \mathrm{O}_{2} \rightarrow 2 \mathrm{O} \cdot

Step 2O∙+O2→O32 \quad \mathrm{O} \bullet+\mathrm{O}_{2} \rightarrow \mathrm{O}_{3}

Step 3O3→O∙+O23 \quad \mathrm{O}_{3} \rightarrow \mathrm{O} \bullet+\mathrm{O}_{2}

Step 4O∙+O3→2O24\quad{O} \bullet+\mathrm{O}_{3} \rightarrow 2 \mathrm{O}_{2}

(a)

Distinguish ultraviolet light from visible light in terms of wavelength and energy.

[ 1 ]
[Maximum number: 1]

Chlorine undergoes many reactions.

(a)
(i)

State the full electron configuration of the chlorine atom.

[ 1 ]
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