From the following list of elements—Ar, H, Ga, Al, Ca, Br, Ge, K, O—pick the one that best fits each description. Use each element only once: (a) an alkali metal, (b) an alkaline earth metal, (c) a noble gas, (d) a halogen, (e) a metalloid, (f) a nonmetal listed in group 1A, (g) a metal that forms a 3+ ion, (h) a nonmetal that forms a 2- ion, (i) an element that resembles aluminum.

Verified step by step guidance

1. Identify the alkali metal: Alkali metals are found in Group 1 of the periodic table. Look for an element in the list that belongs to this group.
2. Identify the alkaline earth metal: Alkaline earth metals are located in Group 2 of the periodic table. Find the element in the list that fits this category.
3. Identify the noble gas: Noble gases are in Group 18 of the periodic table. Determine which element from the list is a noble gas.
4. Identify the halogen: Halogens are found in Group 17 of the periodic table. Select the element from the list that is a halogen.
5. Identify the metalloid: Metalloids have properties intermediate between metals and nonmetals. Choose the element from the list that is a metalloid.

Key Concepts

Periodic Table Groups

The periodic table is organized into groups (columns) that share similar chemical properties. For example, Group 1A contains alkali metals like potassium (K), while Group 2A contains alkaline earth metals like calcium (Ca). Understanding these groups helps identify elements based on their characteristics, such as reactivity and ionization behavior.

Element Categories

Elements can be categorized as metals, nonmetals, or metalloids based on their properties. Metals, such as aluminum (Al), are typically good conductors of heat and electricity, while nonmetals, like oxygen (O), are poor conductors and can form negative ions. Metalloids, such as germanium (Ge), exhibit properties of both metals and nonmetals, making them unique in their applications.

Ionic Charges and Formation

Elements can form ions by gaining or losing electrons, resulting in positive or negative charges. For instance, nonmetals like oxygen (O) typically gain electrons to form anions with a 2- charge, while metals like aluminum (Al) can lose electrons to form cations with a 3+ charge. Recognizing these tendencies is crucial for predicting how elements will interact in chemical reactions.