Periodicity Melting Points And Ionisation Energies

State which definition of a periodic property would secure full marks in an examination.

Explain why first ionisation energies for elements 1–36 are usually plotted on a logarithmic scale rather than a linear scale.

On a graph of first ionisation energy against atomic number for elements 1–36, where do the highest peaks and lowest troughs occur?

State the equation that defines the first ionisation energy of an element X.

Across Period 3 the first ionisation energy generally increases from Na to Ar. Which explanation is correct?

Explain why the first ionisation energy of aluminium is lower than that of magnesium.

Explain why the first ionisation energy of sulfur is lower than that of phosphorus.

State which Period 3 element has the highest melting temperature and the reason for this.

Explain why the melting temperature of sulfur is higher than that of phosphorus.

A student claims that the first ionisation energy decreases down Group 1 “because the nuclear charge gets smaller”. Which statement correctly identifies and corrects the error?

A research team discovers a hypothetical element Z just below krypton with atomic number 54. Based purely on periodicity, which prediction about its first ionisation energy is most reasonable?

Compare and rank the first ionisation energies of N, O, and F in increasing order.

State why the melting temperature of magnesium is higher than that of sodium.

An unknown Period 3 element has a first ionisation energy of 1012 kJ mol⁻¹, higher than both of its immediate neighbours. Which element is it most likely to be?