Question

Two pure elements react to form a compound. One element is an alkali metal, X, and the other element is a halogen, Z. Which of the following is the most valid scientific claim that can be made about the compound?a. It has the formula XZ2
b. It does not dissolve in water.
c. It contains ionic bonds.
d. It contains covalent bonds.

Answer 1

Answer:

Option c. It contians ionic bonds

Explanation:

Let's take as an example NaCl

An element from group 1 (alkali) with an halogen.

Elements from group 1 form cations with +1 (charge)

This ionic salt, can't never has the formula XZ₂

Ionic salts, also can be dissolved in water, and they don't contain covalent bonds.

Answer 2

Answer: C. It contains ionic bonds.

Explanation: Ionic bonds are formed as a result of electrostatic force of attraction between a positively charged ion (cation) and a negatively charged ion (anion).

An alkali metal is a member of the group one elements such as lithium, sodium and potassium which have one electron in their outermost shell while a halogen is a member of group seven elements such as fluorine, chlorine and bromine which have seven electrons in their outermost shell. X will lose its valence electron in order to attain a stable octet or duplet structure thus becoming positively charged while X will gain the electron lost by X in order to attain a stable octet structure thus becoming negatively charged.