Ionic and Molecular Compounds

Question 1

What are the two types of chemical bonds?

Answer 1

ionic compounds and molecular compounds

Question 2

What is a chemical bond?

Answer 2

the force of attraction holding two atoms or ions together in a compound

Question 3

What forces hold together ionic bonds and what is their arrangement?

Answer 3

many ionic forces - electrostatic forces)
- arranged in a giant lattice structure (regular gird-like arrangement)

Question 4

What are ionic compounds composed of?

Answer 4

metal and non meal

Question 5

What are the characteristics of ionic compounds?

Answer 5

• hard and brittle
• relatively high melting and bioling points
• conduct electricity as molten liquids
• conduct electricty when dissolved in water (electrolytes)

Question 6

Explain the high melting point in ionic compounds

Answer 6

ions are held together by strong electrostatic forces which are hard to break apart

Question 7

Why are ionic compounds hard?

Answer 7

the bonds in crystal lattive resist being stretched

Question 8

Why are ionic compounds brittle?

Answer 8

when an external force strikes the crystal lattice, the distribution of ions is disrupted and alike charges may now become side by side creating a repulsive force and breaking them apart.

Question 9

What is an electrolyte?

Answer 9

when a free floating ions are dissolved in a liquid that can then carry elecctric charges.

Question 10

AS A SOLID, ionic compounds cannot conduct electricity because their ions are bonded in a lattice.

Question 11

• Ions have either a positive or negative charge
• there is a transfer of electrons between atoms to create an ionicc bond

Question 12

There is no single unit made up of a single sodium and chloride ion -> THERE ARE NO MOLECULES OF NACl

Question 13

what is a formula unit

Answer 13

the smallest repeating unit in an ionic crystal

Question 14

what is an ionic compound composed of

Answer 14

composed of a huge number of formula units

Question 15

What must you put around an ion?

Answer 15

SQUARE BRACKETS (and charge)

Question 16

What are molecular compounds composed of?

Answer 16

two or more non-metals

Question 17

What are the characteristics of molecular compounds?

Answer 17

• can be solid, liquid or gas
• solids can be soft, waxy, flexible or crystalline
• low melting/boiling points
• poor electric conudctivity when dissolved in water
• poor electrical conductivity in the liquid state

Question 18

Molecular compounds form Molecules

Question 19

Explain the melting/boiling points in a molecular compound.

Answer 19

the force of attraction between moleccules is lower than an ionic bond

Question 20

Why can’t molecular compounds conuduct electricity

Answer 20

there are no ions formed, there is limited ability to cconduct electricity

Question 21

Spearmint and Caraway have the same elements and quantity of elements, but they are flipped and are completely different substances

Question 22

What is a molecular element?

Answer 22

a pure substance composed of molecules made up ot two or more atoms of the same element (diatomic)

Question 23

what is a molecular compound

Answer 23

a pure substance composed of molecules usually made up of two or more non-metallic elements (like water)

Question 24

what is bonding capacity

Answer 24

the number of covalent bonds an atom can form. The bonding capacity is usually equivalent to the number of unpaired electrons in the valence shell of an atom

Question 25

What is a resonance structure?

Answer 25

when a double (multiple) bond can be on multiple places on a molecule

Question 26

what is the equation for formal charge?

Answer 26

formal charge = # of valence electrons -# of unbonded ele ctrons - (#of unbonded electrons/2)

Question 27

For neutral molecules, the sum of the formal charges must add up to zero

Question 28

For ions, the sum of formal charge must equal the charge of the ion.

Question 29

formal charges DO NOT indicate actual charge separation witthin a molecule, just helps us keep track of valence electrons in molecule

Question 30

If a lewis structure is a non-zero formal charge, try to change the structure such that it is 0