Question

use the periodic table to locate lithium, barium, and cobalt. match the element with the correct description.

forms colorful compounds
is most reactive
has 2 valence electrons

lithium
barium
cobalt

Explanation:

Locate elements on the periodic table

• Lithium (\(\text{Li}\)) is in Group 1 (Alkali Metals), Period 2.
• Barium (\(\text{Ba}\)) is in Group 2 (Alkaline Earth Metals), Period 6.
• Cobalt (\(\text{Co}\)) is in Group 9 (Transition Metals), Period 4.

Analyze chemical properties

• Alkali metals (Group 1) are highly reactive, with reactivity increasing down the group. However, comparing Lithium (Group 1), Barium (Group 2), and Cobalt (Transition Metal), Group 1 elements are generally the most reactive. Thus, lithium is most reactive.
• Alkaline earth metals (Group 2) have 2 valence electrons. Barium, being in Group 2, has 2 valence electrons.
• Transition metals are known for forming colorful compounds due to partially filled d-orbitals. Cobalt is a transition metal that forms colorful compounds.

Match elements to descriptions

• lithium: is most reactive
• barium: has 2 valence electrons
• cobalt: forms colorful compounds

Answer:

Use the periodic table to locate lithium, barium, and cobalt. Match the element with the correct description:

• lithium: <blank>is most reactive</blank>
• barium: <blank>has 2 valence electrons</blank>
• cobalt: <blank>forms colorful compounds</blank>