Term | Definition |
Atomic Number | The number of protons in the nucleus. Protons = Electrons |
Electron | Negatively charged subatomic particle. Found outside of the nucleus. 1/2000 the mass of a proton or neutron. |
Proton | Positively charged subatomic particle found in the nucleus. |
Neutron | Subatomic particle with no charge found in the nucleus |
Period | Horizontal row of the elements. It also stands for the number of electron shells around the element. Example Carbon is in period 2 so it has 2 electron shells. |
Group/Family | Vertical column of elements with similar but not identical properties. Same number of valence electrons. |
Valence
Electrons | Electrons in the outer shell. This is where covalent bonds are formed between non-metals. |
Atomic mass | Average mass of protons and neutrons in the nucleus. To find the average number of neutrons in an element subtract the atomic number from the atomic mass. |
Atomic Mass Unit (AMU) | Unit used to measure subatomic particles. Protons and neutrons have a mass of 1 amu. |
Alkali Metals | This family has 1 valence electron. |
Mercury | This element is liquid at room temperature and found in the transition metals. |
Nitrogen | This family has 5 valence electrons |
Halogen | This family is made up of extremely reactive non metals. |
Thorium | This element has 90 electrons. |
Noble Gases | This family is unreactive and inert. |
Boron | This family has 3 valence electrons. |
Transition Metals | This family's electrons can jump between electron shells and usually has 1 or 2 valence electrons. |
Subscript | Number in the lower right hand corner that represents the number of atoms of an element in a compound. |
Carbon | This family has 4 valence electrons |
Krypton | This element has 8 valence electrons |
Strontium | This element has 5 electron shells. |
Selenium | This element has 45 neutrons. |
Molecule | combination of two or more atoms. |
Chemical Symbol | Shorthand way to represent an element |
Subatomic Particles | Proton, neutron, and electron |
Metals | These are on the left side of the zigzag on the periodic table |
Non-metals | These are on the right side of the zigzag on the periodic table |
Magnesium | This element has an atomic number of 12 |
Copper | This element has an atomic mass of 64. |
Gold | Symbol Au stands for what element? |
Energy Level | Location of electrons in the electron cloud. |
Compound | Anything made up of two or more elements (must be different elements). |
Octet Rule | Rule of thumb that elements tend to bond so each atom has 8 valence electrons in their outer shell. |
Coefficient | Number placed in front of the symbol or a formula in a chemical equation that indicates how many atoms or molecules of this substance are involved in the reaction. |
Alkaline Metals | This family loses both of its valence electrons when it bonds. |
Oxygen | This element has 6 valence electrons. |
Mass Number | The sum of protons and neutrons in the nucleus. This is the exact number for as isotope. |
Black | Color used to represent a carbon atom in a molecule. |
Red | Color used to represent an oxygen atom in a molecule. |
Blue | Color used to represent a nitrogen atom in a molecule. |
White | Color used to represent a hydrogen atom in a molecule. |
Coefficient | Number that is placed in front of a symbol or a formula that indicates how many atoms or molecules of this substance are involved in the reaction. |
Sodium | This element is in period 3. |
Mass Number | Sum of the protons and neutrons in the nucleus of an atom. |
Electron Cloud | Space in which electrons are likely to be found. |
Atom | Smallest part of an element that has all of the properties of the element. |
Chemical Equation | Expression in which symbols, formulas, and numbers are used to represent a chemical reaction. |
Isotope | Atom that has the same number of protons(atomic number) as another atom but has a different number of neutrons. |