The Periodic Table

Flashcards about The Periodic Table, including its history, structure and key trends.

The Periodic Table

Organizes elements to showcase trends in their physical and chemical properties.

Periods

Rows in the periodic table.

Groups

Columns in the periodic table.

Elements in the same group

Have the same number of valence electrons, which gives them similar chemical properties.

Group 1: Alkali Metals

Highly reactive, especially with water.

Alkali Metals

Reaction with water demonstrates the increasing reactivity as you move down the group.

Group 2: Alkaline Earth Metals

Reactive but less so than alkali metals; they have two outer electrons.

Group 7: Halogens

Highly reactive, needing just one electron to complete their outer shell.

Group 8: Noble Gases

Stable and unreactive due to their full outer electron shells.

Elements in the same period

Have the same number of electron shells, but increasing atomic number across the period results in different chemical properties.

Robert Boyle (1661)

Defined an element as a substance that cannot be broken down into simpler substances by chemical means.

Dobereiner’s Triads

Grouped elements in threes, where the atomic mass of the middle element was approximately the average of the other two.

Newlands’ Octaves

Arranged elements by increasing atomic mass and noticed that every eighth element had similar properties.

Mendeleev’s Periodic Table (1869)

Arranged elements by increasing atomic weight and predicted the properties of undiscovered elements by leaving gaps in his table.

Moseley’s Modern Periodic Table (1913)

Reorganised the table based on atomic number, solving inconsistencies in Mendeleev’s table.

Atomic Radius

Increases down a group and decreases across a period.

Ionisation Energy

The energy required to remove the most loosely bound electron.

Ionisation Energy Trends

Decreases down a group and increases across a period.

Electronegativity

The ability of an atom to attract electrons in a chemical bond.

Electronegativity Trends

Decreases down a group and increases across a period.

Modern Periodic Table

Organises elements by atomic number.