Explanation:
Across the same period, metals have lower ionization energies than non-metals due to lower nuclear charges with the same number of shells (shielding effect).

Explanation:
Each $\mathrm{Cl}$ ligand has a 1-charge.
2+(4x−1)=2−.
As outlined in the Chemistry Guide, [CuCl4]^2− has a tetrahedral shape.

Metalloids lie on the boundary between metals and non-metals in the p block of the periodic table. They are shiny like metals but brittle like non-metals, and can switch between being electrical insulators and electrical conductors. Although this switchable conductivity could be considered as a change from metal-like to non-metal-like behaviour, it does not affect all properties of the element: the element does not switch from being a metal to a non-metal.

Metalloids do not contain incomplete d subshells (this is a property of transition metals) and lie alongside the poor metals in the p block of the periodic table. This question is categorised as moderately difficult as the concept of metalloids is not covered extensively in the syllabus, though the distinction between metals, non-metals and metalloids is highlighted.

Explanation:
Choices III and IV are ethene and ethyne with a double bond and a triple bond, respectively. They belong to the classes of alkenes and alkynes, which can be deduced by the general formulae, CnH2n and CnH2n−2 .
Choice I is the alkane methane, and choice II is a halogenoalkane (chloromethane).

Explanation:
Group 17 melting points increase down the group due to increased strength in intermolecular forces. The molecular structures of each element are held together by London (dispersion) forces. These increase with the number of electrons in the molecule. Therefore statement I is not true, but III is.
Group 1 melting points decrease down a group due to decreasing metallic bond strength (with increase of atomic radius), therefore statement II is also true.

Explanation:
Recall of transition metal properties.

Explanation:
The overall charge on the complex ion is $1-$, water is neutral and the chloride ion has a charge of $1-$ = $+$ Cr.
Cr has an oxidation state of 3+.

Explanation:
1 and 2 are enantiomers, exhibiting opposite optical activities (rotate plane polarised light in opposite directions by the same amount).
Compound 3 is achiral, so it has a rotation angle of 0 degrees.
This question is in the “hard” category, as the student must be able to determine a molecule's chirality and recall how polarimetry can be used to distinguish between stereoisomers.

Explanation:
Saturated compounds contain only single bonds.
Butyne is an alkyne, and so, has a triple bond.

Explanation:
The longest carbon chain has 5 carbons and will include the C=C.
The alkene is given priority and is on carbon-1.
The methyl group is bonded to carbon-2.

Explanation:
The student must recognise that there are three proton environments in a 3:2:3 ratio;
B has only $2$ environments ($3:2$ ratio), while C has 4 (3:2:2:1). D has $3$ environments but they are in a 6:1:1 ratio.
The question is hard as two pieces of information must be extracted from the spectrum and interpreted in the context of the structural formulas given.

Explanation:
Atomic radius and metallic character decrease across a period. Ionization energy decreases down a group due to increased shielding.

Explanation:
The charges of the positive and negative ions must cancel out to give an overall neutral compound. Group 2 metals form ions with a 2+ charge. The formulae of the counterions above are: $.$

Explanation:
Structural isomers have the same molecular formula but different structural formulae.
Methoxyethane and propanol both have the molecular formula C3H8O.

Explanation:
In HBrO, the oxidation states of both H and Br are +1.

Explanation:
This question tests the ability of the student to convert a 3D model to wedge-dash notation.
The difficulty is low as the shape of the model is close to that of the 2D representation – no rotation around the single bonds is needed to determine the relative orientations of the substituent groups.

Carbon-1 is attached to an H-atom coming out of the page (wedge bond), an NH2 group going into the page (dashed bond), and a CH3 group in the plane of the page.
Carbon-2 is attached to a $\mathrm{Cl}$ atom coming out of the page (wedge bond), an H atom going into the page (dashed bond), and a CH3 group in the plane of the page.

Explanation:
Ligands are Lewis bases with a lone pair of electrons that they can donate to a central metal ion.

Explanation:
NH3 has a non-bonding pair of electrons it can donate to a central metal ion. BH3 and CH4 do not have non-bonding electrons.

Explanation:
A tertiary amine is when three carbon groups are attached to the amine.

Explanation:
Group 2 metal oxides produce alkaline metallic hydroxides when dissolved in water.

Explanation:
Statement II is incorrect as acids produce solutions with $\mathrm{pH}$ lower than 7

Explanation:
The student must recognise that the described technique is IR spectroscopy, and correctly interpret the diagram to identify a wavelength in the IR range.
The question is of moderate difficulty as it requires both the definition and the diagram to be understood correctly.

Explanation:
Increasing atomic radius results in a weaker electrostatic force of attraction between the nucleus and electrons in the covalent bond. An increased number of shells down the group increases the shielding between the nucleus and electrons in the covalent bond.

Explanation:

Elements in the same group (column) of the periodic table have the same number of outer shell (valence) electrons, represented by the group number; the number of electron shells increases down the group. Elements in the same row (period) have the same number of electron shells (or principal quantum number), equal to the period number; the number of valence electrons increases across the period. This question is moderately difficult as the student must recall multiple pieces of information and correctly interpret a schematic illustration of the periodic table.