(a) Without looking at a periodic table, list as many alkali metals as you can. (There are five common ones.)

Alkali metals are a group of elements found in Group 1 of the periodic table. They are characterized by having a single electron in their outermost shell, which makes them highly reactive, especially with water. The five common alkali metals are lithium (Li), sodium (Na), potassium (K), rubidium (Rb), and cesium (Cs). Their reactivity increases down the group, and they are known for forming strong bases when reacting with water.

The periodic table is a systematic arrangement of elements based on their atomic number, electron configuration, and recurring chemical properties. Elements are organized into rows (periods) and columns (groups), with alkali metals located in the first column. Understanding the periodic table is essential for predicting the behavior of elements, including their reactivity and the types of compounds they can form.

The reactivity of metals refers to how readily a metal will undergo a chemical reaction, often with nonmetals or acids. Alkali metals are particularly reactive due to their low ionization energy, which allows them to easily lose their outer electron. This property is crucial for understanding their behavior in chemical reactions, such as their vigorous reactions with water to produce hydrogen gas and metal hydroxides.