Chemistry Practice (Interactive)

What is the electron configuration of a potassium atom (atomic number 19)?

The first ionisation energies of elements across Period 3 generally increase, but there is a notable decrease between magnesium (Mg) and aluminium (Al). What is the reason for this decrease?

Which type of bonding involves the sharing of electron pairs between atoms, and can be either polar or non-polar depending on the electronegativity difference?

What is the molecular shape of a molecule of methane (CH4), according to VSEPR theory?

What volume of gas is produced at room temperature and pressure (RTP) when 0.5 mol of magnesium reacts completely with excess hydrochloric acid? The equation is: Mg + 2HCl -> MgCl2 + H2 (molar volume at RTP = 24 dm3/mol).

A solution of sodium hydroxide has a concentration of 0.2 mol/dm3. What volume of this solution is required to prepare 250 cm3 of a 0.05 mol/dm3 solution by dilution?

What is the pH of a solution with a hydrogen ion concentration of 0.001 mol/dm3?

In a titration, 25.0 cm3 of 0.1 mol/dm3 sodium hydroxide is neutralised by sulfuric acid of unknown concentration. If 12.5 cm3 of the acid is required, what is the concentration of the sulfuric acid? The balanced equation is: 2NaOH + H2SO4 -> Na2SO4 + 2H2O.

Which homologous series has the general formula CnH2n and contains a carbon-carbon double bond?

Which type of isomerism describes molecules that have the same molecular formula but different structural arrangements of atoms?