Bonds

Question 1

What is a covalent bond

Answer 1

Electrostatic attraction between the shared pair of electrons and the positive nuclei

Question 2

Ionic bond

Answer 2

An electrostatic attraction between positive ions and negative ions

Question 3

Metallic bond

Answer 3

An electrostatic attraction between positive ions and delocalised electrons

Question 4

What happens in coordinate bonding

Answer 4

Both electrons are donated from 1 atom to the empty orbital of another

Question 5

What is the shape of a simple molecule determined by

Answer 5

The electrons and bonds in it. This is because electron pairs repel each other and therefore try to get as far away as possible

Question 6

Shapes of simple covalent molecules
2 pairs of electrons

Answer 6

Linear molecule
180 degrees

Question 7

Shapes of simple covalent molecules
3 pairs of electrons

Answer 7

Trigonal planar
120 degrees

Question 8

Shapes of simple covalent molecules
4 pairs of electrons

Answer 8

Tetrahedral
109.5 degrees

Question 9

Shapes of simple covalent molecules
5 pairs of electrons

Answer 9

Trigonal bipyramidal
120 degrees & 90 degrees

Question 10

Shapes of simple covalent molecules
6 pairs of electrons

Answer 10

Octahedral (8 faces)
90 degrees

Question 11

What affects the shape of an atom

Answer 11

As well as bonding pairs of electrons repelling, any lone pairs that are around the central atom also affects the shape

Question 12

What repels more lone pairs or bonding pairs

Answer 12

Lone pairs repel more

Question 13

4 pairs of electron
3 bonding
1 lone pair

Answer 13

Pyramidal
107.5 degrees

Question 14

4 pairs of electrons
2 bonding pairs, 2 lone pairs
( e.g. H20)

Answer 14

V - shaped / bent
104.5 degrees

Question 15

5 pairs of electrons
4 bonding, 1 lone pair

Answer 15

Modified Trigonal bipyramid

Question 16

5 pairs
3 bonding, 2 lone pairs

Answer 16

T shaped

Question 17

6 pairs
4 bonding, 2 lone pairs

Answer 17

Square planar

Question 18

How to determine the shape

Answer 18

1) group number of central atom
2) number of bonding atoms
3) charge
4) add up and divide by 2
5) work out lone pairs , total - bonding

Question 19

What is electronegativity

Answer 19

The ability of an atom to attract the pair of electrons(/electron density) in a covalent bond towards itself

Question 20

What would happen with Cl2 due to electronegativity

Answer 20

Nothing would happen because there is no difference in electronegativity, so we have a non-polar covalent bond

Question 21

Ht would happen in HCL due to electronegativity

Answer 21

Chlorine is more electronegative that hydrogen , this is a polar bond

Question 22

What does electronegativity depend on

Answer 22

• nucleus charge
• atomic radius
• electron shielding

Question 23

What is the most electronegative element

Answer 23

F
Fluorine

Question 24

How to increase electronegativity

Answer 24

More protons and a smaller radius increases attraction from the nucleus

Question 25

What decreases electronegativity

Answer 25

More shielding decreases the attraction from the nucleus

Question 26

What elements are relatively electronegative

Answer 26

N , nitrogen O , oxygen Cl , chlorine

Question 27

where are intermolecular forces commonly found?

Answer 27

they exist between simple covalent molecules. these are the forces between individual molecules

Question 28

what are they 3 types of IMF?

Answer 28

- van de Waals force (weakest) - dipole-dipole force - hydrogen bond ((strongest) but weak compared to real bonds)

Question 29

how is a van der waals force formed?

Answer 29

electrons in an atom are unevenly distributed making a temporary dipole. this induces a dipole in the nearby atom. this creates an attraction between them

Question 30

the affect of an atoms size on van der Waals forces

Answer 30

this bigger the Mr of the atom/molecule, the larger the van der Waal force is, which increases the boiling point

Question 31

which atoms have van der Waals forces

Answer 31

all atoms and molecules have van der Waals forces

Question 32

when does dipole-dipole forces occur

Answer 32

when the delta+ and the delta- in a molecule are permanent

Question 33

how are the dipole-dipole forces formed

Answer 33

the delta+ end of one molecule attracts the delta- end of an adjacent molecule

Question 34

what molecules can have dipole-dipole forces

Answer 34

asymmetric polar molecules as they have a net dipole moment

Question 35

when would hydrogen bonds occur

Answer 35

only happens when hydrogen is bonded to a small electronegative atom with in a molecule N, O, F

Question 36

when drawing a hydrogen bond, what do you have to ensure

Answer 36

- all delta charges on involved atoms - 180 degrees - all lone pairs are on the diagram