bonding

Question 1

What are the three types of chemical bonding?

Answer 1

Ionic, covalent, metallic

Question 2

What is ionic bonding?

Answer 2

The electrostatic attraction between oppositely charged ions.

Question 3

How are ions formed?

Answer 3

by the transfer of electrons, resulting in either the gain of electrons or the loss of electrons

Question 4

What type of structure do ionic compounds form?

Answer 4

A giant ionic lattice.

Question 5

What are the key properties of ionic compounds?

Answer 5

High melting points

Question 6

What is covalent bonding?

Answer 6

A shared pair of electrons between two non-metals.

Question 7

What is a double and triple covalent bond?

Answer 7

Double = 2 shared pairs; triple = 3 shared pairs.

Question 8

What is a dative covalent bond?

Answer 8

A covalent bond where both electrons come from the same atom.

Question 9

Examples of dative bonding?

Answer 9

Ammonium ion (NH₄⁺)

Question 10

What is metallic bonding?

Answer 10

Electrostatic attraction between positive metal ions and a sea of delocalised electrons.

Question 11

Properties of metals explained by metallic bonding?

Answer 11

High melting/boiling points

Question 12

What are the three types of intermolecular forces?

Answer 12

Van der Waals (induced dipole), permanent dipole dipole forces, and hydrogen bonding (N,O, F)

Question 13

What causes van der Waals forces?

Answer 13

random movement of electrons in one molecule creates a dipole
this induces a temporary dipole in the neighbouring molecule
these temporary dipoles attract

Question 14

When are van der Waals forces present?

Answer 14

Between all molecules but dominant in non-polar molecules.

Question 15

What causes permanent dipole-dipole forces?

Answer 15

Polar molecules with permanent dipoles attract each other.

Question 16

How can you tell if a molecule is polar?

Answer 16

It must have polar bonds and an asymmetric shape so dipoles don’t cancel.

Question 17

What is hydrogen bonding?

Answer 17

A strong dipole-dipole attraction between H attached to N, O, or F

Question 18

Examples of hydrogen bonding?

Answer 18

Water (H₂O)

Question 19

Effects of hydrogen bonding?

Answer 19

High boiling points of water and alcohols

Question 20

What is electronegativity?

Answer 20

The ability of an atom to attract the bonding electrons in a covalent bond.

Question 21

Which element is the most electronegative?

Answer 21

Fluorine.

Question 22

What is a polar bond?

Answer 22

A covalent bond between atoms with different electronegativities.

Question 23

What theory is used to predict shapes of molecules?

Answer 23

Electron Pair Repulsion Theory (VSEPR).

Question 24

What determines the shape of a molecule?

Answer 24

The number of bonding and lone electron pairs around the central atom.

Question 25

Why do lone pairs reduce bond angles?

Answer 25

Lone pairs repel more strongly than bonding pairs.

Question 26

What causes different melting points in covalent substances?

Answer 26

Molecular = weak intermolecular forces; Giant covalent (e.g. diamond

Question 27

Why do giant ionic lattices have high melting points?

Answer 27

Strong electrostatic forces between ions require lots of energy to overcome.

Question 28

Why does graphite conduct electricity but diamond does not?

Answer 28

Graphite has delocalised electrons that can move; diamond does not.

Question 29

Why is ice less dense than water?

Answer 29

Hydrogen bonds hold molecules in a lattice with more open space.

Question 30

What is the shape and bond angle of a molecule with 2 bonding pairs and 0 lone pairs?

Answer 30

Linear

Question 31

What is the shape and bond angle of a molecule with 3 bonding pairs and 0 lone pairs?

Answer 31

Trigonal planar

Question 32

What is the shape and bond angle of a molecule with 4 bonding pairs and 0 lone pairs?

Answer 32

Tetrahedral

Question 33

What is the shape and bond angle of a molecule with 3 bonding pairs and 1 lone pair?

Answer 33

Trigonal pyramidal

Question 34

What is the shape and bond angle of a molecule with 2 bonding pairs and 2 lone pairs?

Answer 34

Bent (V-shaped)

Question 35

What is the shape and bond angles of a molecule with 5 bonding pairs and 0 lone pairs?

Answer 35

Trigonal bipyramidal

Question 36

What is the shape and bond angle of a molecule with 6 bonding pairs and 0 lone pairs?

Answer 36

Octahedral

Question 37

Why do lone pairs reduce bond angles in molecular shapes?

Answer 37

Because lone pairs repel more strongly than bonding pairs

Question 38

how do van der Waals forces arise? (3)

Answer 38

- random movement of electrons creates a temporary dipole in one molecule - this induces a dipole in the neighbouring molecule - these temporary dipoles attract