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Chemical Substances - Elements and Symbols

Grade 6Cambridge (IGCSE)

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

🔑Concepts

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

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

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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.

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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.

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

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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).