| A | B |
|---|
| Atom | Smallest part of an element that can still be identified as that element. |
| Democritus | Greek philosopher that named smallest particle atom, after "atomos". |
| Dalton | Started laws in the atomic theory: 1) All substances are made of atoms. 2) Atoms are small particles that cannot be created, divided, or destroyed. 3) Atoms of same element are alike, atoms of different elements are different. 4) Atoms can join together to make new substances |
| Nucleus | Center or core of an atom where protons and neutrons are located. |
| Electrons | Negatively charged particle, found outside the nucleus. |
| Energy level | Place in electron cloud where electrons are most likely to be found. |
| J.J. Thomson | Scientist that discovered the electron using catho rade tubes. |
| Rutherford | Scientist that discovered the proton (sort of) and nucleus using his gold foil experiment. |
| Atomic number | The number of Protons in the nucleus of the atom. |
| Mass number | The total number of protons and neutrons in the nucleus of the atom. |
| Illustrate | To represent using drawings and pictures. |
| Orbit | To revolve around |
| Electron clouds | The regions inside an atom where an electron is likely to be found. |
| Protons | Positively charged particle in an atom, found in the nucleus. |
| Neutrons | Neutrally charged particle in an atom, found in the nucleus. |
| Isotopes | Atoms that have the same number of protons but have different numbers of neutrons. |
| Atomic mass unit | SI unit used to express the masses of particles in atoms. |
| Atomic mass | weighted average of the masses of all the naturally occurring isotopes of an element. |
| Metals | Elements on the periodic table located to the left of the zig zag line. Have the properties of malleability, ductility, and conductivity. |
| Nonmetals | Elements on the periodic table located to the right of the zig zag line, that are dull and are poor conductors of thermal energy and electric current. |
| Metalloids | Elements located on the zig zag line that have properties of both metals and nonmetals. |
| Group | Vertical column on the periodic table. |
| Period | Horizontal row on the periodic table. |
| Pattern | A repeating sequence |
| Periodic | Repeating pattern |
| Luster | The ability to reflect light. (Shiny) |
| Element | Pure substance that cannot be chemically or physically broken down into a simpler substance. |
| Reactive | When two or more substance get together and something happens creating a new substance. |
| Alkali Metal | Elements found in group 1 that are soft, low density, silver colored, shiny, and EXTREMELY reactive. Have 1 valence electron. |
| Alkaline Earth Metals | Elements found in group 2 that are silver colored, low density (higher than Alkali metals), and VERY reactive. Have 2 valance electrons. |
| Transition Metals | Elements in groups 3-12 that are shiny, good conductors, higher densities (than AM + AEM), and SORT OF reactive. Have 1 or 2 valence electrons. |
| Lanthanides | Transition Metals on the top period that was kicked out of the Periodic Table. |
| Actinides | Transition Metals on the bottom period that was kicked out of the Periodic Table. |
| Halogens | Elements found in group 17 that are poor conductors, react violently with alkali metals, and always found combined in nature. Have 7 valence electrons |
| Noble Gases | Elements found in group 18 that are colorless, odorless gases at room temperature. Most have 8 valence electrons, but one has 2. UNCREATIVE |
