What would you expect the combining ratio to be for alkali metals to be with a halogen? With oxygen?

2 Answers
Mar 10, 2017

Answer:

The combining ratio for alkali metals and halogens is #1:1#.

The combining ratio for alkali metals and oxygen is #2:1#.

Explanation:

Alkali metals form #1^+# ions. Halogens form #1^-# ions. Oxygen forms #2^-# ions.

Ionic compounds are neutral, so the total positive charge has to equal the total negative charge.

Alkali metals plus halogens: potassium and chlorine

#"K"^+ + "Cl"^(-)##rarr##"KCl"#

The combining ratio for alkali metals and halogens is #1:1#.

Alkali metals plus oxygen: potassium and oxygen

#"2K"^+ + "O"^(-2)##rarr##"K"_2"O"#

The combining ratio for alkali metals and oxygen is #2:1#.

Mar 10, 2017

Answer:

Alkali metals all have a single valence electron, and halogens have a single missing one, so they would combine in a 1:1 ratio.

Oxygen requires two more valence electrons to complete its shell, so it would combine in a 2:1 ratio.

Explanation:

Elements combine (react) to form more stable compounds based on their electronic structure – specifically the valence electrons.

Groups 1, 2, and 17 (halogens) have only one more stable configuration, and Group 16 have a primary configuration, but may also have additional ones. The “transition metals” have a variety of possible stable electronic configurations with other elements. https://www.webelements.com/