Vocabulary
Chemistry Vocabulary Periodic Trends, Quantum Mechanics, Atomic Theory, Ionic & Covalent Bonding
1. Group
- The columns of elements on the periodic table.
2. Periods
- The rows of elements on the periodic table.
3. Element
- A substance that cannot be broken down into simpler substances by chemical means.
4. Compound
-A compound is a substance formed when two or more chemical elements are chemically bonded together.
5. Atomic Number
- The atomic number of a chemical element (also known as its proton number) is the number of protons found in the nucleus of an atom of that element, and therefore identical to the charge number of the nucleus.
6. Atomic Mass
- Atomic mass or atomic weight is the average mass of atoms of an element.
7. Atom
- The smallest object that retains properties of an element. Composed of electrons and a nucleus (containing protons and neutrons).
8. Ion- An atom or molecule which has gained or lost one or more of its valence electrons , giving it a net positive or negative electrical charge.
9. Valence Electron
- An electron in one of the outer shells of an atom that can participate in forming chemical bonds with other atoms.
10. Metal
- Elements that form cations when compounds of it are in solution and oxides of the elements form hydroxides rather than acids in water.
11. Nonmetal
- One of the elements which do not exhibit metallic properties, generally located in the upper righthand corner of the Periodic Table .
12. Metalloids
- A metalloid is a chemical element that has properties in between those of metals and nonmetals.
13. Noble Gas
- Any of the seven chemical elements that make up the rightmost group of the periodic table as usually arranged: helium, neon, argon, krypton, xenon, radon, and element 118.
14. Alkali Metal
- Any of a group of soft, white, low-density, low-melting, highly reactive metallic elements.
15. Alkaline Earth Metal
- An alkaline earth metal is an element belonging to group 2 of the periodic table. The alkaline earth metals, as a group, share characteristic properties.
16. Halogen
- Any of a group of five chemically related nonmetallic elements including fluorine, chlorine, bromine, iodine, and astatine.
17. Cation
- A positive ion; an atom or group of atoms that has lost one or more electrons.
18. Anion
- A negatively charged ion.
19. Electron Affinity
- Electron affinity reflects the ability of an atom to accept an electron . It is the energy change that occurs when an electron is added to a gaseous atom. Atoms with stronger effective nuclear charge have greater electron affinity.
20. Electronegativity (explain the trend)
- As you move across a period electronegativity increases, and as you move down a group it decreases.
21. Ionization Energy (explain the trend)
- As you move across a period ionization energy increases and as you move up a group it increases as well.
22. Atomic Radii (explain the trend)
- As you move down a group, atomic radius increases, and as you move across a period it decreases.
23. Density
- Mass of a unit volume of a material substance. It is calculated by dividing an object's mass by its volume.
24. Melting Point
- Temperature at which the solid and liquid forms of a pure substance can exist in equilibrium. As heat is applied to a solid, its temperature will increase until the melting point is reached.
25. Reactivity
- Reactivity then refers to the rate at which a chemical substance tends to undergo a chemical reaction in time. In pure compounds, reactivity is regulated by the physical properties of the sample.