Topic V Test Review

Two atoms of H become a molecule of H₂. Which statement is true?

• Energy is absorbed as a bond is broken.

• Energy is released as a bond is formed.

• Energy is released as a bond is broken.

• Energy is absorbed as a bond is formed.

Answer explanation

when atoms bond they become more stable which means losing energy

Which compound has covalent bonds?

• NaI

• CuO

• HCl

• LiF

Answer explanation

covalent bonds are between nonmetals

Which element has metallic bonds at room temperature?

• barium

• chlorine

• oxygen

• carbon

Answer explanation

metals have metallic bonds due to mobile valence electrons

The least polar bond is found in a molecule of

• HF

• HI

• HBr

• HCl

Answer explanation

Find the one with the lowest END

A solid sample of zinc is an excellent conductor of electric current. Which type of chemical bonds are in the sample?

• metallic bonds

• nonpolar covalent bonds

• polar covalent bonds

• ionic bonds

Answer explanation

Zn is a metal, so metallic bonds

Which formula represents an asymmetrical molecule?

• CO₂

• CH₄

• N₂

• HCl

Answer explanation

It is not symmetrical....the electrons are not distributed equally

Which phrase describes the molecular polarity and distribution of charge in a molecule of carbon dioxide, CH₄?

• nonpolar and asymmetrical

• polar and symmetrical

• nonpolar and symmetrical

• polar and asymmetrical

Answer explanation

symmetrical so nonpolar

symmetrical means equal distribution of electrons

• Both compounds are ionic.

• Compound 1 is molecular, and compound 2 is ionic.

• Both compounds are molecular.

• Compound 1 is ionic, and compound 2 is molecular.

Answer explanation

ionic have higher MP, BP, and conduct when (l) or (aq) because it is a stronger bond than covalent

Molecular compounds are opposite as they are weaker bonds

This is electron-dot diagram for calcium chloride.

• True

• False

Answer explanation

CaCl₂

_{Ionic (M and NM) so needs brackets around the NM and electrons and ion charges must be written.}

A solid sample of a compound and a liquid sample of the same compound are each tested for electrical conductivity. Which test conclusion indicates that the compound is covalent?

• Both the solid and the liquid are good conductors.

• The solid is a good conductor, and the liquid is a poor conductor.

• The solid is a poor conductor, and the liquid is a good conductor.

• Both the solid and the liquid are poor conductors.

Answer explanation

Between 2 NMs means no ions produced ever, as electrons are shared. They are therefore not great conductors no matter the phase or polarity.