SC5/6/7 Ionic Bonding Flashcards
SC5a
1) What are bonds?
2) What are ions?
3) What is a cation?
4) What is an anion?
1) Bonds are forces of attraction that hold atoms together.
2) An ion is an atom or group of atoms with a positive or negative charge. Ions form when atoms lose or gain electrons to obtain a full outer shell.
3) A cation is a positive ion formed when metal atoms lose electrons.
4) An anion is a negative ion formed when non metals gain electrons.
SC5a
1) What are electrostatic forces?
2) What is the difference between an atom and an ion?
1) Electrostatic forces are the forces between positively and negatively charged objects. These forces hold the oppositely charged ions together, and form an ionic bond between them.
2) An atom has the same number of protons and electrons so an atom has no overall electric charge. An ion has a positive or negative charge through losing or gaining electrons.
SC5b
1) What is an ionic lattice?
2) What do ions ending in -ite or -ate mean?
3) What does an ion ending in -ide mean?
1) An ionic lattice is the regular repeating arrangement in an ionic compound, held together by strong electrostatic forces between oppositely charged ions.
2) This means that the ions contains oxygen as well as another element.
3) If there are two atoms in an ionic compound, the name ending of the non-metal changes to ide.
SC5c
1) What kind of melting and boiling points do ionic compounds have and why.
2) When do ions conduct electricity?
3) Why do ions only conduct electricity in these circumstances?
4) When do ionic compounds not conduct electricity and why?
1) They have high melting and boiling points. Ionic compounds are held together by many strong electrostatic forces. As the ionic lattice contains such a large number of ions, a lot of energy is needed to overcome these ionic bonds so ionic compounds have high melting and boiling points.
2) Ionic compounds conduct electricity when molten to form a liquid or dissolved in water to form an aqueous solution.
3) A substance can conduct electricity if it contains charged particles, and these particles are free to move from place to place.
4) Ionic compounds cannot conduct electricity when solid, as their ions are held in fixed positions and cannot move.
SC6a
1) What are covalent bonds?
2) Recall the names of 7 common molecular elements
1) A covalent bond is formed when a pair of electrons is shared between two atoms, usually non-metals.
2) They are Hydrogen, Oxygen, Nitrogen and all the halogens: Fluorine, Chlorine, Bromine, Iodine.
SC6a
1) What is the approximate size of atoms and small molecules?
2) What is the type of bonding found in molecules?
3) What is valency?
1) A simple molecule contains only a few atoms, so the sizes of atoms and simple molecules have a similar range of sizes - they are very small, typically around 0.1 nm (1 × 10 to the power of -10 metres) across.
2) Molecular substances are held together by covalent bonds.
3) Valency is the number of covalent bonds formed by atoms of different elements.
SC7a
1) What are intermolecular forces?
2) What kind of boiling and melting points do simple molecular compounds have and why?
3) Can simple molecular compounds conduct electricity and why?
1) Intermolecular forces are weak forces of attraction between molecules.
2) Simple molecular compounds often have low boiling and melting points because it doesn’t take much energy to overcome the weak intermolecular forces between them.
3) Simple molecules have no delocalised electrons, or charged particles that can separate, so simple molecular substances cannot conduct electricity, even when liquid or dissolved in water.
SC7a
1) What are polymers?
2) What do most polymers contain and why?
1) Polymers are monomers that have joined together in a chain.
2) Most polymers contain a chain of carbon atoms. This is because carbon atoms can form up to four covalent bonds with other atoms, and so monomers are usually linked together by covalent bonds between carbon atoms.
SC7b
1) What are 4 allotropes of carbon?
2) What are the differences between covalent, simple molecules and giant covalent structures?
1) Allotropes of carbon include: diamond, graphite, fullerenes and graphene.
2) Simple covalent substances generally have low melting/boiling points, as they have weak intermolecular forces. Giant covalent substances, contain many strong covalent bonds in a 3D lattice structure, so they have very high melting/ boiling points.
SC7b
1) Explain the properties and uses of diamond in terms of its structure and bonding
2) Explain the properties and uses of graphite in terms of its structure and bonding
1) Diamond has the following physical properties:
It does not conduct electricity, it is a good conductor of heat
It has a very high melting point
It is extremely strong
Diamond is used in for coating blades in cutting tools because it is strong
2) Graphite has the following physical properties:
It conducts electricity and heat
It has a very high melting point
It is soft and slippery and less dense than diamond
It is used in pencils and as an industrial lubricant in machines because it is soft and slippery.
SC7c
1) Why are metals malleable?
2) Why do metals conduct electricity?
3) What are the properties of metals?
4) What are the properties of non-metals?
5) Describe the particles and how they are arranged in metal
1) Metals are malleable because layers of ions can slide over each other when a force is applied. Metallic bonding allows the metal to change shape without shattering.
2) When a voltage is applied to a metal, the delocalised electrons travel through the lattice structure. The movement of these charged particles forms an electric current.
3) Metals: have high melting points, have high boiling points, are good conductors of heat and electricity, and are malleable.
4) Non metals: have low melting points, are poor conductors of heat and electricity, and are brittle.
5) The structure of a solid metal consists of closely packed metal ions, arranged in a regular way to form a metallic lattice structure.
SC7d
1) How are different types of bonds and structures formed (ionic and covalent)?
2) How is the structure and bonding of a substance linked to its physical properties?
3) Why do we use models to express structure and bonding?
1) Ionic bonds are formed by the loss and gain of electrons to produce oppositely charged ions that attract one another.
Simple molecular (covalent) bonds are formed when atoms share pairs of electrons.
2) The physical properties of a giant covalent substance is determined by its structure. The strength of the covalent bonds between the atoms in a giant covalent structure determines the melting and boiling point of these structures.
3) Different bonding models explain and illustrate observations of different forms of bonding.
SC7d
Describe the advantages and disadvantages of the different models used to represent structure and bonding: dot and cross, ball and stick, 2D, 3D
Dot and Cross Diagrams
Advantages:
Useful for illustrating the transfer of electrons
Indicates from which atom the bonding electrons come from
Disadvantages:
Fails to illustrate the 3D arrangements of the atoms and electron shells
Doesn’t indicate the relative sizes of the atoms
Ball and Stick Model
Advantages:
Useful for illustrating the arrangement of atoms in 3D space
Especially useful for visualizing the shape of a molecule
Disadvantages:
Fails at indicating the movement of electrons
The atoms are placed far apart from each other, which in reality is not the case as the gaps between atoms are much smaller
2D Representations of Molecules
Advantages:
Displayed formulae are 2D representations and are basically simpler versions of the ball and stick model
Adequately indicate what atoms are in a molecule and how they are connected
Disadvantages:
Fail to illustrate the relative sizes of the atoms and bonds
Cannot give you an idea of the shape of a molecule and what it looks like in 3D space
3D Representations of Ionic Solids
Advantages:
3D drawings and models depict the arrangement in space of the ions
Also show the repeating pattern in giant lattice structures
Disadvantages:
Only illustrate the outermost layer of the compound
Are difficult and time-consuming to draw
SC7c
1) Describe the structures of diamond and graphite
2) Describe the structures of fullerenes and graphene
1) Diamond is a giant covalent substance in which: each carbon atom is joined to four other carbon atoms by strong covalent bonds. The carbon atoms form a regular tetrahedral network structure, so there are no freely moving charged particles.
In graphite, each carbon atom in graphite is bonded to three others forming layers of hexagons, leaving one free (delocalised) electron per carbon atom. Each layer is held together by weak intermolecular forces.
2) Fullerenes are molecules of carbon atoms with hollow shapes. Their structures are based on hexagonal rings of carbon atoms joined by covalent bonds. Each carbon atom is joined to 3 other carbon atoms, leaving on delocalised electron per carbon atom.
In graphene, each carbon atom in graphite is bonded to three others forming one layer of hexagons, leaving one free (delocalised) electron per carbon atom. Graphene’s structure resembles a single layer of graphite.
SC7c
Recall the names of 5 common molecular compounds
They are ammonia, carbon dioxide, methane, sulphur dioxide, and water
