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Chem Vocab Definitio
Chapter 4
| Term | Definition |
|---|---|
| Bohr Model | The scientist responsible for the Solar System model of the atom: the first person to place electrons into energy levels |
| Alkali Metal | The elements of Group I of the Periodic Table |
| Democritus | Ancient philosopher who coined the term "atomos" |
| Groups/Family | A horizontal row of elements in the periodic table |
| Elements that are chemically similar to each other | |
| Noble Gases | The elements of Group VIII of the Periodic Table |
| John Dalton | Credited with the first scientifically-based theory about the atom [Theory with 5 postulates] |
| Mass Number | The sum of the numbers of protons and neutrons in the nucleus of an atom |
| James Chadwick | Credited with the discovery of the neutron |
| Oxidation Number | Number that indicates the number of atoms or polyatomic ions in a formula |
| Isotope | An atom that has the same number of protons As other atoms of the same element do but that has a different number of neutrons |
| J.J. Thomson | Scientist who discovered the electron and developed the 'Plumb Pudding Model" of the atom |
| Equivalent to the charge on an atom or ion | |
| Cation | A positively charged ion |
| Halogens | The elements of Group VII of the Periodic Table |
| Scientist who discovered that the atom is mostly empty space and has a small, dense nucleus | |
| Anion | A negatively charged ion |
| Atomic Number | This is the number of protons in an atom or an ion |
| Covalent Compounds | A compound composed only of non-metals |
| Diatomic Elements | 7 elements that always occur in pairs in nature; HONClBrIF |
| Alkaline Earth Metal | The elements of Group II of the Periodic Table |
| Polyatomic Ion | A group of covalently bonded atoms that have a charge |
| Valence Electrons | Particles found in the outermost energy level of the atom. The particle that directly takes part in bonding |
| Ionic Compound | Compound composed of a metal and a nonmetal |
| Nucleus | An atom's central region |
| Valence ? | According to the modern theory, a region in an atom where there is a high probability of finding electrons. |