Speedathon 2026 - DAS - O Level Chemitry & Biology - Day 1 скачать в хорошем качестве

Speedathon 2026 - DAS - O Level Chemitry & Biology - Day 1

Atomic Structure | O Level Chemistry (5070) / IGCSE Chemistry | Full Chapter NotesDescription: Master the full chapter on Atomic Structure for O Level Chemistry 5070 and IGCSE Chemistry. Clear explanations, examples, and exam-focused tips.What you will learn: Atomic structure and models Subatomic particles: protons, neutrons, electrons Atomic number, mass number, isotopic notation Isotopes and relative atomic mass (Ar) calculations Electronic configuration (up to Z=20), shells and valence electrons Ions: cations, anions, noble gas configurations Link to Periodic Table groups/periods and properties Basic nuclear ideas and uses of isotopes Common exam-style questions and pitfalls Chapter notes: Key definitions Atom: The smallest particle of an element that retains its chemical properties. Element: A pure substance made of only one type of atom. Compound: A substance formed when two or more elements chemically combine in fixed ratios. Ion: A charged particle formed by loss or gain of electrons. Isotope: Atoms of the same element with the same number of protons but different numbers of neutrons. Subatomic particles and their properties Proton (p): charge +1, relative mass 1, located in nucleus Neutron (n): charge 0, relative mass 1, located in nucleus Electron (e−): charge −1, relative mass ≈0 (1/1836), located in shells around nucleus Atomic number and mass number Atomic number ZZZ: number of protons (also equals number of electrons in a neutral atom). Mass number AAA: total number of protons + neutrons. Neutrons =A−Z=A-Z=A−Z. Isotopic/nuclear notation: e.g., chlorine-35 written as 1735Cl^{35}_{17}\text{Cl}1735​Cl. Isotopes Same element, different neutron numbers (e.g., 12C^{12}\text{C}12C and 14C^{14}\text{C}14C). Chemical properties: nearly identical (same electron structure). Physical properties: can differ (density, boiling point) due to mass differences. Uses: 14C^{14}\text{C}14C for radiocarbon dating 60Co^{60}\text{Co}60Co for radiotherapy/sterilization 131I^{131}\text{I}131I medical tracers 235U^{235}\text{U}235U nuclear fuel (outside core O Level chemistry detail) Relative atomic mass (Ar) Definition: Weighted average mass of an element’s isotopes compared to 1/12 of 12C^{12}\text{C}12C.