Chapter 3 - Bonding

Question 1

How are Chemical Bonds formed?

Answer 1

When electrons are shared/transferred between 2 atoms to obtain a full outer shell, making it more stable

Question 2

What are Ionic Bonds?

Answer 2

Ionic Bonds is the electrostatic force between 2 oppositely charged ions (Metal and Non-Metal)

The ions are formed when they transfer electrons to each other to become stable

Question 3

What do a collection of Ionic Bonds form?

Answer 3

Giant Ionic Lattices/Crystals

Question 4

What Ions do Metals make and why?

What ions do Non-Metals make and Why?

Answer 4

Positive ions as they donate electrons so they have more protons > electrons

Negative ions as they receive electrons so they have more electrons > protons

Question 5

What are Covalent Bonds?

Answer 5

The attraction between the + Nuclei’s and the shared pair of electrons in overlapping orbitals (Non-Metal + Non-Metal)

Note: Orbitals usually contain 2 electrons, so sharing 2 electrons creates a full orbital which increases stability

Question 6

What are Covalent Bonds proportional to?

Answer 6

The amount of orbital overlap

Question 7

What are Dative/Coordinate Covalent Bonds?

Answer 7

Covalent bond where an atom with an unpaired electron shares the pair with a vacant atom

E.g. NH3 and H+ = NH4+

Question 8

How are Dative/Coordinate Bonds shown?

Answer 8

With arrows showing where the pair of electrons is shared with

Question 9

What is a Metallic bond?

Answer 9

The electrostatic forces between electrons and positive metal ions in a regular lattice

Question 10

3 Factors Affecting the Strength of a Metallic Bond

Answer 10

More Protons, more nuclear attraction means stronger bond

More delocalized electrons, increase the strength of the bond

Smaller Atom, increase nuclear attraction which strengthens the bond

Question 11

What are Ionic Crystals?

Answer 11

A solid consisting of many Ionic Bonds

Question 12

3 Properties of Ionic Crystals

Answer 12

High Melting/Boiling point due to strong electrostatic forces

Conduct when molten/in aqueous as bonds break creating ions acting as charge carriers

Brittle and Soluble

Question 13

What are Macromolecular Covalent Crystals?

Answer 13

Giant molecular Structures containing several Covalent Bonds in a regular lattice

Example: Diamond and Graphite

Question 14

What are Allotropes?

Answer 14

Different forms of the same element

Question 15

What are Simplemolecular Covalent Crystals?

Answer 15

Molecules containing a little amount of covalent bonds, intermolecular, vdw, hydrogen, permanent dipole forces

Low melting/boiling point and poor conductors

Examples: I2, H2O, Ice, CO2

Question 16

What is electronegativity?

Answer 16

The ability to attract electrons more than other atoms within a covalent bond

Question 17

Trends/Factors affecting Electronegativity

Answer 17

Increases across a period as if the amount of Protons increase, it will pull electrons in shells closer to it, decreasing the atomic radius

Decrease down a group as atomic radius increases as electrons in shells repel each other

Note: Electronegativity decreases down a group as Atomic Radius overrides the increase in Protons

Question 18

What is polarity?

Answer 18

A property determining whether a covalent bond has an even/uneven distribution of electrons

Question 19

What are Polar Bonds?

Answer 19

When there’s an uneven distribution of electrons, so there’s a + and - side, due to difference in electronegativity

Note: Polar is all bonds are identical, no lone electron pairs

Question 20

What are Non-Polar Bonds?

Answer 20

When electrons are distributed evenly, so everything is either symmetrical or nothing is more electronegative

Symmetrical Molecules: CO2 is symmetrical as it has double bonds which cannot move, whereas H2O isn’t symmetrical as it has single bonds which can rotate

Question 21

What is Polarization?

Answer 21

How strong partial charges on a molecule are

Note: If polarization is big enough, electrons may transfer. In Covalent Bonding sharing means elements have similar electronegativity

Question 22

What is Polarization dependent on?

Answer 22

Difference in electronegativity, greater it is, the greater the charges are, increasing reactivity

Question 23

What are Van der Waal Forces?

Answer 23

Transient/Induced Dipoles between molecules.

As electrons move randomly, theres a change for them to become unevenly distributed to create a temporary weak dipole that effects neighboring molecules to have the opposite charge to it

Question 24

3 Factors affecting Vdw Forces

Answer 24

More outer electrons, higher chance to become dipole, creating stronger vdw and high melting/boiling point

Increasing Atomic Radius, electrons can move easier to create vdw forces easier

Greater Area of Surface contact, creates more Vdw as theres more neighboring molecules increasing Melting/Boiling point

Question 25

What are Permanent Dipole-Dipole Forces?

Answer 25

Weak Electrostatic Force between opposite partial charges on 2 polar molecules

Example: HCL/NF

Question 26

What are Hydrogen Bonds?

Answer 26

An electrostatic force between hydrogen. Strongest out of the 3 and have the highest melting/boiling point