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Chemical Substances - Elements and Symbols

Grade 6IGCSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

An element is a pure substance consisting of only one type of atom. It cannot be broken down into simpler substances by chemical means.

Each element is represented by a unique chemical symbol. For example, Carbon is represented as CC and Oxygen as OO.

Chemical symbols follow a strict capitalization rule: the first letter is always uppercase, and the second letter (if present) is always lowercase, such as NaNa for Sodium or MgMg for Magnesium.

Some elements exist naturally as diatomic molecules, meaning two atoms of the same element are bonded together, such as H2H_2, O2O_2, and N2N_2.

Some symbols are derived from Latin names. For instance, FeFe comes from Ferrum (Iron), CuCu from Cuprum (Copper), and AuAu from Aurum (Gold).

The Periodic Table is an arrangement of all known elements based on their atomic properties and characteristics.

📐Formulae

H2 (Hydrogen molecule)H_2 \text{ (Hydrogen molecule)}

O2 (Oxygen molecule)O_2 \text{ (Oxygen molecule)}

N2 (Nitrogen molecule)N_2 \text{ (Nitrogen molecule)}

Cl2 (Chlorine molecule)Cl_2 \text{ (Chlorine molecule)}

P4 (Phosphorus molecule)P_4 \text{ (Phosphorus molecule)}

S8 (Sulfur molecule)S_8 \text{ (Sulfur molecule)}

💡Examples

Problem 1:

Identify the element name for the symbol NaNa and explain its origin.

Solution:

Sodium

Explanation:

The symbol NaNa stands for Sodium. It is derived from its Latin name, Natrium.

Problem 2:

What is the difference between the notations CoCo and COCO?

Solution:

CoCo is an element, while COCO is a compound.

Explanation:

Following the rules of chemical symbols, CoCo (capital CC, lowercase oo) represents the single element Cobalt. COCO (two capital letters) represents a compound made of Carbon (CC) and Oxygen (OO).

Problem 3:

Write the chemical symbol for the following elements: Helium, Iron, and Potassium.

Solution:

Helium: HeHe, Iron: FeFe, Potassium: KK

Explanation:

Helium uses the first two letters of its name (HeHe). Iron uses its Latin root Ferrum (FeFe). Potassium uses its Latin root Kalium (KK).

Elements and Symbols - Revision Notes & Key Formulas | IGCSE Grade 6 Science