Test--Lewis Structures and Intermolecular Forces

What are valence electrons?

• electrons that are closest to the nucleus

• electrons that are in d orbitals

• electrons that are in the outermost s and p orbitals

• electrons that do not form bonds

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

How many valence electrons are in aluminum?

• 13

• 3

• 10

• 8

Tags

NGSS.HS-PS1-1

How many electrons are in the Lewis dot structure for germanium (Ge)?

• 14

• 32

• 28

• 4

Tags

NGSS.HS-PS1-1

How are the electrons arranged in the Lewis dot structure for selenium (Se)?

• two pairs and two single electrons

• three pairs and no single electrons

• no pairs and six single electrons

• four pairs and no single electrons

How many valence electrons are in a molecule of sulfur difluoride (SF_²)?

• 50

• 20

• 18

• 15

Tags

NGSS.HS-PS1-1

You are drawing a Lewis structure for the carbonate ion (CO₃^2-). You count four electrons for the carbon atom and eighteen electrons for the three oxygen atoms for a total of 22 valence electrons. How does the -2 charge affect the total number of valence electrons?

• You would add two more valence electrons for a total of 24.

• You would subtract two valence electrons for a total of 20.

• You would not change the number of valence electrons so the total would be 22.

• You would add four more valence electrons because there are four atoms in the ion.

Tags

NGSS.HS-PS1-2

When do you need to use double or triple bonds in a Lewis structure for a molecule?

• when there are more than four atoms around the central atom

• when it will make the molecule more symmetrical

• when you have too many valence electrons for the structure

• when there aren't enough valence electrons to give all atoms that need an octet eight electrons

Which of the following elements does not require an octet of electrons when bonded?

• hydrogen

• beryllium

• boron

• All of these are correct. (None of these require an octet.)

Which of the following molecules would have at least one double bond? (Hint: Draw Lewis structures for each molecule.)

• phosphate ion (PO₄^3-)

• nitrate ion (NO₃^1-)

• carbon tetrachloride (CCl₄)

• sulfur difluoride (SF₂)

How many unshared electron pairs are there in the Lewis structure for phosphorus tribromide (PBr₃)?

• 0

• 1

• 2

• 3