Atomic str

Notes

Atomic structure and the periodic table C2 Topic 1 • Mendeleev arranged the elements in order of increasing atomic number • He arranged elements with similar properties into vertical columns (groups) • He left gaps and predicted the existence and properties of the missing elements The periodic table Metals and non-metals Non-metals Metals The structure of an atom • Atoms are made from three types of subatomic particle • The nucleus contains protons and neutrons • The nucleus is surrounded by electrons arranged in electron shells or energy levels • The nucleus of an atom is very small compared to the overall size of an atomnucleus • Every atom of a given element has the same number of protons in the nucleus. This number is unique to that element • Atoms contain equal numbers of protons and electrons. This means that they have no overall charge Subatomic particles = same as number of electrons Using the periodic table Protons: (atomic no.) -13 Electrons: (same as no. of protons/atomic no.) - 13 Neutrons: (mass no. – atomic no.) - 27-13 = 14 • Atomic number (proton number): is the number of protons in an atom - The elements are arranged in the Periodic Table in ascending order ...