- Periodic Table

2. a table of the chemical elements arranged in order of atomic number, usually in rows, so that elements with similar atomic structure (and hence similar chemical properties) appear in vertical column
7. each of more than one hundred substances that cannot be chemically interconverted or broken down into simpler substances and are primary constituents of matter. Each element is distinguished by its atomic number, i.e. the number of protons in the nuclei of its atoms.
8. also known as the nucleon number, is the total count of protons and neutrons in the nucleus of a specific atom

1. a characteristic of matter that can be observed or measured without changing its chemical identity, meaning the substance remains the same on a molecular level
3. an atom or molecule with a net electric charge due to the loss or gain of one or more electrons
4. is the region around an atom's nucleus where electrons are most likely to be found, representing a probability distribution rather than a fixed orbit
5. a one- or two-letter abbreviation used to represent a chemical elemen
6. the number of protons in the nucleus of an atom, which uniquely identifies a chemical element