Pearson Edexcel GCSE (9-1) Chemistry study guide
Key concepts in chemistry Study Guide
Review study guide for Key concepts in chemistry in Edexcel Chemistry.
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Key concepts in chemistry
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Atomic Structure and Subatomic Particles
Atoms are the fundamental building blocks of all matter. Each atom consists of a nucleus containing protons and neutrons, surrounded by electrons orbiting in shells. The identity of an element is determined by the number of protons, known a
Atoms are the fundamental building blocks of all matter. Each atom consists of a nucleus containing protons and neutrons, surrounded by electrons orbiting in shells. The identity of an element is determined by the number of protons, known as the atomic number (Z). In a neutral atom, the number of electrons equals the number of protons. The mass number (A) represents the total number of protons and neutrons in the nucleus. By using these two numbers, we can calculate the number of each subatomic particle for any given atom.
Formation of Molecules by Covalent Bonding
When atoms form covalent bonds, they share pairs of electrons, resulting in the creation of molecules. Molecules are discrete groups of atoms held together by shared electrons. This is distinct from ionic bonding, where ions are formed. Cov
When atoms form covalent bonds, they share pairs of electrons, resulting in the creation of molecules. Molecules are discrete groups of atoms held together by shared electrons. This is distinct from ionic bonding, where ions are formed. Covalent bonding commonly occurs between non-metal atoms, such as in water (H₂O) or oxygen (O₂). Each molecule formed by covalent bonding consists of a specific number and type of atoms joined together through these shared electron pairs.
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