Periodicity and the Periodic Table

Vocabulary flashcards covering Topic 8: Periodicity, including Periodic Table structure, blocks, groups, periods, trends across Period 3, atomic radius, and ionisation energies.

Periodic Table

A list of all the elements arranged in order of increasing atomic number.

Metalloids (Semi-metals)

Elements that touch the stepped 'staircase line' dividing metals from non-metals, possessing a combination of metallic and non-metallic properties.

s-block

The area of the Periodic Table containing all elements that have their highest energy electrons in s-orbitals.

p-block

The area of the Periodic Table containing all elements that have their highest energy electrons in p-orbitals.

d-block

The area of the Periodic Table containing all elements that have their highest energy electrons in d-orbitals.

Transition metals

d-block elements that form compounds in which they have partly filled d-orbitals, excluding scandium and zinc.

Origin of s, p, d, and f labels

Historical terms used to describe lines appearing in the spectrum of light emitted by elements: sharp ($s$), principal ($p$), diffuse ($d$), and fine ($f$).

Group

A vertical column of elements forming a chemical 'family' with similar properties and the same number of electrons in the outer main level.

Period

A horizontal row of elements in the Periodic Table.

Lanthanides

A series of metals (atomic numbers 58 to 71) that all tend to form $+3$ ions in their compounds and display broadly similar reactivity.

Actinides

Radioactive metals (atomic numbers 90 to 103) of which only thorium and uranium occur naturally in the Earth's crust in more than trace quantities.

Periodicity

The regularly recurring trends and patterns in physical and chemical properties of elements across periods of the Periodic Table.

Covalent radius

Half the distance between the centres of a pair of covalently bonded atoms, commonly used as a measure of atomic size.

First ionisation energy

The energy required to convert a mole of isolated gaseous atoms into a mole of singly positively charged gaseous ions ($E(g) \rightarrow E^+(g) + e^-(g)$).

Shielding

The effect whereby filled inner electron energy levels reduce the nuclear attraction experienced by outer shell electrons.

Successive ionisation energies

The energies required to remove electrons from an atom one after another, with each subsequent electron requiring more energy to remove than the previous one.