Isotopes
Atoms with the same number of protons, but different numbers of neutrons.
Mass Number
The total number of protons and neutrons in an atom’s nucleus.
Atomic Number
The number of protons in an atom’s nucleus.
Atomic Structure
Mass number goes in the top left corner, atomic number goes in the bottom left corner, element symbol goes in the center, and charge goes in the top right corner.
Valence Electrons
The electrons located in the outermost shell of an atom that are the ones involved in chemical bonding.
Groups/Families
The vertical columns. There are 18 groups in total, numbered 1 to 18, and elements within the same group share similar chemical and physical properties due to having the same number of valence electrons.
Periods
Horizontal rows of elements. Each period represents the energy level occupied by the valence electrons of the elements within that row.
Alkali Metals
Group 1; These elements share similar properties due to their single valence electron, making them highly reactive and typically found in compounds rather than as free elements.
Alkaline Earth Metals
Group 2; These elements are characterized by having two valence electrons.
Transition Metals
Groups 3-12; This group of elements is located in the d-block of the periodic table, specifically in groups 3 through 12. They are characterized by having partially filled d orbitals in their atomic or ionic form, which contributes to their unique properties.
Halogens
Group 17; A group of highly reactive, non-metallic elements containing 7 valence electrons.
Noble Gases
Group 18; Group of chemical elements characterized by their extremely low reactivity. Their lack of reactivity stems from their stable electron configurations, specifically having a full valence shell.
Ionic Formula Naming
1) Name the cation/metal first.
- If the metal has a fixed charge, then simply write the name of the metal.
- If the metal has a variable charge, then write the name of the metal and in Roman numerals, write the charge given in the formula.
2) Name the anion/nonmetal second with an -IDE ending.
Covalent Formula Naming
1) Write the name of the first element.
2) Write the name of the second element with an –IDE ending.
3) Use prefixes to show how many atoms of each type there are (but do not use the “mono” prefix on the first element).
Mixtures
A physical combination of two or more substances where each substance retains its original chemical identity and properties and can be separated by physical means; can be classified as homogeneous or heterogeneous.
Homogeneous Mixture
A mixture having visibly indistinguishable parts; AKA a solution.
Heterogeneous Mixture
A mixture have visibly distinguishable parts.
Pure Substance
Matter that has a single, uniform chemical composition and is made of only one type of atom or molecule.
Compound
A substance with constant composition that can be broken down into elements by chemical processes.
Element
A substance that cannot be decomposed into simpler substances by chemical or physical means.
Elements
Substances that cannot be decomposed into simpler substances by chemical or physical means.
Physical Change
A change in the form of a substance, not in its chemical composition; chemical bonds are not broken in a physical change. For example, boiling and freezing: When water freezes or boils, it changes its state but remains water.
Chemical Change
A change in which a given substance becomes a new substance or substances with different properties and different composition, such as iron rusting to form iron oxide; a chemical reaction.
The Law of Conservation of Masses
States that mass is neither created nor destroyed in a chemical reaction.
