Strontium has two valence electrons. It is located in group 2 of the periodic table, which is also known as the alkaline earth metals. Elements in this group typically have two electrons in their outermost shell.
To understand why strontium has two valence electrons, let’s look at its electron configuration. The electron configuration for strontium (Sr) is [Kr] 5s2. This shows that in addition to the core electrons that make up the noble gas configuration of krypton, there are two electrons in the 5s subshell that are considered valence electrons.
These valence electrons are important because they determine how strontium will react chemically with other elements. Typically, strontium will lose these two electrons to form a +2 oxidation state and will participate in ionic bonding in compounds.