The Periodic Table: Development and Structure

This page focuses on the development and structure of the periodic table, a fundamental concept in atomic structure and the periodic table combined science curricula.

The early 1800s saw elements arranged by atomic weight and properties. In 1869, Dmitri Mendeleev arranged 50 known elements into his table, marking a significant advancement in chemical understanding.

Highlight: Mendeleev's innovation was leaving gaps and reversing the order of elements to ensure they fell into the correct groups based on their properties.

The modern periodic table, as described in BBC Bitesize atomic structure and the periodic table resources, is arranged by increasing atomic number and sorted into:

1. Groups: Elements with similar properties (vertical columns)
2. Periods: Rows representing new shells of electrons

The page also introduces the classification of elements into metals, non-metals, and transition metals, which is crucial for understanding element properties and reactivity.

Definition: The atomic number is the number of protons in an atom's nucleus, which determines the element's identity.

This organization of the periodic table is essential for predicting element properties and understanding chemical behavior, topics frequently covered in Chemistry AQA GCSE atomic structure past papers.

Separating Mixtures

This final page covers methods for separating mixtures, a practical application of chemical principles often examined in periodic table GCSE Edexcel and other exam boards.

The page details three separation techniques:

1. Chromatography:
   • Used to separate different components in a mixture
   • Involves a stationary phase (filter paper) and a mobile phase (solvent)

Example: Separating different dyes in ink

2. Filtration:
   • Separates insoluble solids from liquids
   • Uses filter paper folded into a cone shape

Vocabulary:

• Residue: The solid left in the filter paper
• Filtrate: The liquid that passes through the filter

3. Evaporation:
   • Used to separate a soluble solid from a solution

These separation techniques are fundamental to practical chemistry and are often featured in atomic structure and the periodic table past papers.

Understanding these methods is crucial for both theoretical knowledge and practical skills in chemistry, aligning with the requirements of AQA periodic table printable resources and exam questions.