Correct Answer: Option 4: Alkaline metal group

Key Points

• The elements lithium (Li), sodium (Na), and potassium (K) belong to the alkali metal group in the periodic table.
• Alkali metals are located in Group 1 of the periodic table and are characterized by having one electron in their outermost shell.
• These metals are highly reactive, especially with water, and they tend to form strong alkaline hydroxides.
• Alkali metals are known for their low melting and boiling points compared to other metals.
• As you move down the group from Li to Na to K, the reactivity increases significantly.

Why Other Options Are Wrong

• Alkaline earth metal group: This group includes elements like beryllium (Be), magnesium (Mg), calcium (Ca), and others, which are in Group 2 of the periodic table. They have two electrons in their outer shell and are less reactive than alkali metals.
• Halogen group: Halogens are located in Group 17 of the periodic table and include elements like fluorine (F), chlorine (Cl), and bromine (Br). They are nonmetals and are known for their high reactivity, especially with alkali metals, but they are not related to Li, Na, and K.
• Zero group: The zero group refers to the noble gases, which are located in Group 18. These gases, such as helium (He), neon (Ne), and argon (Ar), are characterized by their lack of reactivity due to having a full outer electron shell.

Quick Tip for Exam

Remember that alkali metals are always found in Group 1 of the periodic table. They include Li, Na, K, Rb, Cs, and Fr. Knowing the group characteristics can help you quickly identify relationships between elements during exams.