Chemical Bonding

Complete the statement:

The octet rule states that atoms tend to form bonds so that each atom has​ (a)  

electrons in its ​ (b)  

• inner shell
• protons
• neutrons
• eight
• valence shell
• two
• one
• seven
• neucleus

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

According to the octet rule, the number of chlorine ions that would bond with a calcium ion is

(a)  

• 2
• 1
• 6

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Which statement best describes a metallic substance

• Metals have low melting and boiling points and are brittle.

• Metals conduct electricity and are malleable.

Tags

NGSS.MS-PS3-3

Select the statement that best describes covalent bonds

• Covalent bonds result from metal atoms exchanging at least some of their valence electrons to form an octet.

• Covalent bonds form when atoms of nonmetals are close enough to each other for their orbitals to overlap resulting in shared electrons.

Tags

NGSS.MS-PS1-1

Which of the following Lewis structures for H₂O are correct? Select all that apply.

• 
• 
• 
• 

Tags

NGSS.MS-PS1-1

Organic chemists identified four different liquids of varying volatilities that they want to test further. They want to compare the overall volatility and intermolecular forces of these liquids. Look at the picture. The circles above the liquid represent the relative number of particles that have evaporated from the liquid. A beaker with a large number of circles above the liquid would have a higher volatility than a beaker with only a few circles above the liquid. Which option correctly ranks the liquids in the order of increasing intermolecular forces?

• IV

• Second STRONGEST intermolecular forces

• III

• WEAKEST intermolecular forces

• I

• second WEAKEST intermolecular forces

• II

• STRONGEST intermolecular forces

Answer explanation

The beaker with the most gas particles above the liquid is the most volatile. This liquid has the WEAKEST intermolecular forces. This is the liquid that will boil at the lowest temperature (it's particles are already starting to evaporate.) The liquid with the lowest volatility has the highest boiling point because the molecules in the liquid have the STRONGEST intermolecular attractions.

Which of the molecules has the highest boiling point?

• Liquid 1: CH₄

• Liquid 2: CH₃CH₃

• Liquid 3: CH₃CH₂CH₃

• Liquid 4: CH₃CH₂CH₂CH₃

Answer explanation

For nonpolar molecules, the bigger the molecule (the more electrons), the stronger the London Dispersion Forces between the molecules, the higher the boiling point.

Tags

NGSS.HS-PS1-3

Select the statement that best describes the difference between the compound Br₂ and the compound NaBr.

• The melting point of NaBr would be significantly HIGHER than that of Br₂ because NaBr is an ionic compound whereas Br₂ is a covalent compound.

• The melting point of NaBr would be significantly LOWER than that of Br₂ because NaBr is an ionic compound whereas Br₂ is a covalent compound.

Answer explanation

NaBr is a metal and a nonmetal atom bonded together.

This must be an ionic compound.

Ionic compounds have high melting points due to the strong attractive forces between ions.

Br₂ is two nonmetals bonded together.

This must be a covalent compound.

Covalent compounds have low melting points due to the weak attractions between molecules (especially nonpolar molecules like Br₂)

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

Select the statement that best describes the difference between the compound O₂ and the compound K₂O

• K₂O would be a solid at room temperature because K₂O is an ionic compound whereas O₂ is a covalent compound.

• O₂ would be a solid at room temperature because O₂ is a covalent compound whereas K₂O is an ionic compound.

Answer explanation

K₂O is metal and a nonmetal atoms bonded together.

This must be an ionic compound.

Ionic compounds have high melting points due to the strong attractive forces between ions.

O₂ is two nonmetals bonded together.

This must be a covalent compound.

Covalent compounds have low melting points due to the weak attractions between molecules (especially nonpolar molecules like O₂)

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

The melting point of CBr₄ suggests that it can be classified as an ionic compound.

• True

• False

Answer explanation

This compound is made of nonmetal atoms.

This must be a covalent compound.

Tags

NGSS.HS-PS1-3