click below
click below
Normal Size Small Size show me how
Chem Chap4
definitions
Term | Definition |
---|---|
Element | A substance that cannot be split into simpler substances by chemical means |
Compound | A number of elements chemically combined. |
Triad | A group of 3 elements with similar chemical properties in which the atomic weight of the middle element is approximately the average of the 1st and 3rd. |
Newlands' Octaves | The elements are arranged in order of increasing atomic weight and the 1st and 8th have similar chemical properties. |
Mendeleev's Periodic Law | The elements are arranged according to atomic mass and the properties vary periodically. |
Atomic Number | The amount of protons in the nucleus of an atom. |
Modern Periodic Table | The elements are arranged in increasing atomic number and the properties vary periodically. |
Mass Number | The sum of the protons and neutrons in the nucleus of an atom |
Isotopes | Atoms of the same element that have the same atomic number but different mass number due to the different amount of neutrons in the nucleus. |
Relative Atomic Mass | The average of the mass of the isotopes of an elements, as they occur naturally and taking their abundances into account. |
Aufbau Principle | When building up an electronic configuration of an atom in its ground state, the electrons must occupy the lowest available energy level. |
Hund's Rule of Maximum Multiplicity | When there are two or more orbitals of the same equal energy the electrons much fill them singly before in pairs. |
Pauli Exclusion Principle | Only two electrons can occupy and orbital and they must have opposite spin. |