Unit 2 Terms

3. Describes an atom or ion that can have more than one valence, or charge, allowing it to bond with multiple other atoms. Transition metals, for example, are often multivalent.
6. metal Any of the reactive metallic elements found in Group 2 of the periodic table, such as magnesium and calcium. They have two valence electrons and readily lose both to form a +2 ion.
9. A vertical column of elements in the periodic table. Elements in the same group share similar chemical properties because they have the same number of valence electrons.
10. element An element in Groups 1, 2, and 13-18 of the periodic table, also known as a main-group element. These elements have their valence electrons in s or p orbitals and represent the wide range of properties found across the table.
11. Describes an atom or ion with a valence of one, meaning it typically gains, loses, or shares one electron to form a chemical bond.

1. gas Any of the elements in Group 18, including helium, neon, and argon. With a full outer electron shell, they are largely unreactive, or inert, under normal conditions.
2. The tendency of an atom or compound to undergo a chemical reaction. It is influenced by the stability of its electron configuration and other factors like bond strength.
4. metal Any of the highly reactive metallic elements found in Group 1 of the periodic table, including lithium, sodium, and potassium. They have one valence electron and readily lose it to form a +1 ion.
5. Any of the highly reactive, nonmetallic elements in Group 17, which includes fluorine, chlorine, and bromine. They have seven valence electrons and tend to gain one to form a -1 ion.
7. A horizontal row of elements in the periodic table. The number of the period corresponds to the highest energy level that an element's electrons occupy.
8. law States that when elements are arranged in order of increasing atomic number, there is a periodic repetition of their chemical and physical properties.