Bonding

Question 1

What type of bonding exists between metals and non-metals

Answer 1

Ionic bonding

Question 2

What happens to electrons in ionic bonding

Answer 2

They are transferred from metal to non-metal

Question 3

Describe the nature of an ionic bond

Answer 3

The electrostatic attraction between oppositely charged ions

Question 4

Describe the structure of ionic compounds

Answer 4

Giant ionic lattice of positive and negative ions held together by electrostatic forces

Question 5

Explain the melting point of ionic compounds

Answer 5

High melting point because strong electrostatic forces within ionic lattice which require a great deal of energy to break

Question 6

Explain the electrical conductivity of ionic compounds

Answer 6

Conduct when molten or dissolved because ions can move but do not conduct as a solid because ions held in fixed position in lattice

Question 7

Which would you expect to have a higher melting point, NaCl or MgO and why

Answer 7

MgO because ions are double the charge of NaCl so stronger electrostatic forces

Question 8

What is the formula of the ionic compound Aluminium Sulfate

Answer 8

Al2(SO4)3

Question 9

What happens to electrons in covalent bonding

Answer 9

Electrons are shared between non-metal atoms

Question 10

What is the difference between a single and double covalent bond

Answer 10

Single is 2 shared electrons in bond, double is 4 shared electrons

Question 11

Describe the bonding in diamond

Answer 11

Each carbon is bonded to 4 other carbons in a tetrahedral shape

Question 12

Describe the structure of graphite

Answer 12

Layers of carbon atoms arranged in hexagonal pattern with weak bonds and delocalised electrons between layers

Question 13

Explain why graphite conducts electricity

Answer 13

Delocalised electrons are free to move and carry charge

Question 14

Explain the hardness of diamond

Answer 14

Atoms are held in fixed positions

Question 15

What is a co-ordinate (dative) bond

Answer 15

Where one atom contributes both electrons in a covalent bond

Question 16

Give an example of a molecule with co-ordinate bonding

Answer 16

NH4+, AlCl3NH3, CO

Question 17

Why do molecules have different shapes?

Answer 17

Electron pairs repel each other as far apart as possible.

Question 18

Which has the greater repulsion effect lone pair of electrons or a covalent bond?

Answer 18

Lone pair

Question 19

What is the bond angle in a linear molecule?

Answer 19

180°

Question 20

What is the bond angle in a trigonal planer molecule?

Answer 20

120°

Question 21

What is the bond angle in a tetrahedral molecule ?

Answer 21

109.5°

Question 22

What shape molecule has 6 bonding electron pairs eg SF6, and what is the bond angle

Answer 22

Octahedral, 90 degrees

Question 23

What shape molecule has 5 bonding pairs eg. PCl5 and what are the bond angles

Answer 23

Trigonal bipyramidal, 90 degrees and 120 degrees

Question 24

What is the shape and bond angle of CH4. Why

Answer 24

Tetrahedral, 109.5 degree, electron pairs repel each other as far as possible

Question 25

How do lone pairs affect bond angles

Answer 25

Reduce bonding pair bond angles (by approx. 2 degrees per lone pair) as they repel more than bonding pairs

Question 26

What is the shape and bond angle in water. Why

Answer 26

Bent, 104.5 degree, 4 pairs of electrons including 2 lone pairs

Question 27

What is the shape and bond angle in ammonia. Why

Answer 27

Trigonal Pyramidal, 107. degree, 4 pairs of electrons including 1 lone pair

Question 28

What is the shape and bond angle in SiCl62- Why

Answer 28

Octahedral, 90. degree, 6 bonding pairs of electrons 0 lone pairs

Question 29

Why is the is the bond angle in water less than 180°?

Answer 29

Water contains two bonds and two lone pairs. Lone pairs repel further than bonded pairs of electrons.

Question 30

Where in the periodic table are the most electronegative elements

Answer 30

Top right (not including noble gases)

Question 31

Which is the most electronegative element

Answer 31

Fluorine

Question 32

Which of these bonds will have a dipole? H-C or Cl-C

Answer 32

Cl-C

Question 33

What causes molecule to be polar (2 requirements)

Answer 33

significant differences in electronegativity and asymmetrical shape

Question 34

Why is CCl₄ not a polar molecule?

Answer 34

Symmetrical molecule so dipoles cancel out.

Question 35

Define electronegativity

Answer 35

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

Question 36

What causes bond polarity

Answer 36

Differences in electronegativity between two atoms bonded together

Question 37

Name the 3 types of intermolecular force in order from weakest to strongest

Answer 37

Van der Waals, dipole-dipole and hydrogen bonding

Question 38

Which type of intermolecular force exists between diatomic molecules

Answer 38

Van der waals only

Question 39

Which types of intermolecular force exist in carbon dioxide

Answer 39

Dipole dipole forces

Question 40

Explain how Van der Waals forces arise

Answer 40

Temporary dipoles because of movement of electrons which induce temporary dipoles in neighbouring molecules

Question 41

Explain how dipole dipole forces arise

Answer 41

Partial positive charge attracting partial negative charge

Question 42

Explain why the boiling point of alkanes increase with increasing chain length

Answer 42

More Van der Waals forces

Question 43

Describe the structure of iodine

Answer 43

Molecular lattice of I2 molecules held tougher by Van der Waals forces

Question 44

What 3 elements could be bonded to hydrogen to give hydrogen bonding

Answer 44

Oxygen, nitrogen or fluorine

Question 45

What is a hydrogen bond?

Answer 45

an electrostatic attraction between a proton in one molecule and an electronegative atom in the other.

Question 46

How does hydrogen bonding affect boiling point

Answer 46

Increases boiling point

Question 47

Describe the structure of ice

Answer 47

Regular lattice structure of water molecules held together by hydrogen bonding. Less dense than water

Question 48

Describe the strucutre of metals

Answer 48

Giant metallic lattice of positive metal ions surrounded by delocalised electrons

Question 49

Explain why Mg has a higher melting point than Na

Answer 49

Doubly charged metal ion

Question 50

Explain why metals conduct electricity

Answer 50

Delocalised electrons are free to move and carry charge

Question 51

Explain why metals have high melting points

Answer 51

The delocalised electrons are strongly attracted to the positive metal ions (strong metallic bonds) which requires a lot of energy to overcome