Unit 3 Chemistry(Polarity, Ionic/Covalent, Lewis structures)

Which of the following is the correct formula for Pentaboron nonahydride?

Tags

NGSS.HS-PS1-1

• -3

• -2

• +2

• +3

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

• 
• 
• 
• 

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

What is the correct order of the following bonds in terms of decreasing polarity?

• N-Cl, P-Cl, As-Cl 

• P-Cl, N-Cl, As-Cl

• As-Cl, N-Cl, P-Cl

• As-Cl, P-Cl, N-Cl

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Which phrase is correct?

• The electrons in a bond between two oxygen atoms (O2) are shared equally, and the resulting bond is polar.

• The electrons in a bond between two oxygen atoms (O2) are shared equally, and the resulting bond is nonpolar.

• The electrons in a bond between two oxygen atoms (O2) are shared unequally, and the resulting bond is polar

• The electrons in a bond between two oxygen atoms (O2) are shared unequally, and the resulting bond is nonpolar.

A substance has a low melting point. It does not conduct electricity either when melted or in the solid form. It is most likely: 

• diamond (C)

• copper (Cu)

• calcium oxide (CaO)

• hydrogen sulfide (H2S)

What is the best explanation for why copper conducts electricity?

• It is metal.

• There are extra electrons in copper that can move freely.

• It can absorb photons and then re-emit them

• Its electrons are present in a delocalized “sea” around metal nuclei.

Which of the following offers the strongest explanation for why the melting temperatures of most ionic compounds are far greater than the melting temperatures of most covalent compounds? 

• Ionic bonds are much stronger than the molecular attractions between covalently bonded compounds. 

• Covalent bonds are not as strong as ionic bonds. 

• As a solid, ionic compounds have a very organized crystalline structure which takes a lot of energy to break apart.

• Most covalent compounds have at least one weak bond in their structure that is easily broken when heat is added.

A model of a compound is shown. Which of the following identifies the compound and explains why? 

• Network covalent solid because there are covalent bonds between the atoms.

• Ionic solid because there are positive and negative charges attracted to each other.

• Molecular compounds because metals and nonmetals are sharing electrons.

• Metallic solid because electrons are distributed among the positive nuclei.

Tags

NGSS.HS-PS1-3