Bonding And Structure Flashcards
What are the 3 sub-atomic particles that make up an atom?
- protons
- neutrons
- electrons
Where are the protons and neutrons found?
Nucleus of the atom
Where are the electrons found?
Electron shells orbiting around the nucleus
Relative mass and relative charge of a proton
- relative mass = 1mu
- relative charge = +1
Relative mass and relative charge of a neutron
- relative mass = 1mu
- relative charge = 0
Relative mass and relative charge of an electron
- relative mass = 1/1836 mu
- relative charge = -1
What is an ion?
Ion = a charged particle formed when an atom/ group of atoms loses or gains electrons
Are metal ions positive or negative? Why is this?
Metal ions are always positive because they always lose electrons as their outer shells are almost empty so they lose this shell.
Are non-metal ions positive or negative? Why is this?
Non-metal ions are always negative because they always have an almost full outer shell, so they gain electrons to achieve a full outer shell
What is the basic atomic configuration?
- 2,8,8,2
- shell 1 = max. 2 electrons
- shell 2 = max. 8 electrons
- shell 3 = max. 8 electrons
- shell 4 = max. 2 electrons
Where does any type of bonding occur in an atom?
Only the outer electron shell
Sodium ion formula
Na+
Lithium ion formula
Li+
Potassium ion formula
K+
Ammonium ion formula
NH4+
Silver ion formula
Ag+
Hydrogen ion formula
H+
Magnesium ion formula
Mg2+
Calcium ion formula
Ca2+
Barium ion formula
Ba2+
Zinc ion formula
Zn2+
Copper(ll) ion formula
Cu2+
Iron(II) ion formula
Fe2+
Lead(II) ion formula
Pb2+
Aluminium ion formula
Al3+
Iron (III) ion formula
Fe3+
Chloride ion formula
Cl-
Fluoride ion formula
F-
Bromide ion formula
Br-
Iodide ion formula
I-
Nitrate ion formula
NO3-
Hydroxide ion formula
OH-
Oxide ion formula
O2-
Sulfide ion formula
S2-
Sulfate ion formula
SO4 2-
Carbonate ion formula
CO3 2-
Nitride ion formula
N3-
What is the atomic number?
The total number of protons in an atom
What is the mass number?
The total number of protons and neutrons in the nucleus
What does the group number (column) tell us about an atom’s electron configuration?
Tells us how many electrons there are in the outer shells
What does the period number (row) tell us about an atom’s electron configuration?
Tells us how many electron shells the atom has
What is ionic bonding?
The strong electrostatic attraction between oppositely charged ions
What does ionic bonding occur between?
A metal and a non-metal as these are oppositely charged ions
Question type = ‘Describe how magnesium atoms and chlorine atoms form magnesium ions and chloride ions.’
- think about the formula of the ionic compound = here it’s MgCl2
- then see how many electrons each atom loses/gains = here Mg lose 2 and Cl gains 1
Then write = Each Magnesium atom loses 2 electrons and each chlorine atom gains 1 electron.
How many shells of an atom/ion do we draw when asked for electron configuration?
All shells
Most of the time, how many shells do we draw when asked to draw an ionic compound?
Most of the time it’s just the outer shell, but RTQ just in case!
What does the sign at the top right corner of the square brackets in a dot-cross diagram of an ion indicate?
The charge (e.g 2+, 3- etc..)
What does the number at the bottom right corner of the square brackets of a dot-cross diagram of an ionic compound show?
The number of ions of that element
What is a giant ionic lattice?
The arrangement of an ionic compound in its solid state, where millions of ions are packed together in a regular 3D structure. This extends in every direction until there are no ions left.
Why are ionic compounds brittle?
- brittle = shatter when hit
- when hit, a layer of ions shift, causing like charged ions to go on top of each other.
- as like charges repel, the layers fly apart , as the force of attraction between oppositely charged ions is strong so the force of repulsion is equally strong
- this splits the lattice causing it to shatter
Why can’t ionic compounds conduct electricity as solids but as liquids/molten state or solutions?
Solid ionic compounds are not able to conduct electricity as there are no mobile charge carriers (ions) because they are all bonded together in the giant ionic lattice. However, in its molten/liquid state or in a solution, the ions are mobile, meaning that they can carry an electric current
Why are ionic compounds usually soluble in water?
The H2O molecules in the substance are slightly charged so can attract ions away from the the lattice and make them free to move
Why do ionic compounds have high melting and boiling points?
Ionic compounds have high melting points because they have a giant ionic lattice structure that contains strong ionic bonds due to strong electrostatic attractions between oppositely charged ions. This means that a large amount of heat energy is required to break the many strong ionic bonds of the giant ionic lattice, giving them high melting + boiling points
Covalent bonding
The strong electrostatic attraction between two positive nuclei and shared pairs of electrons
What does covalent bonding only occur between?
Only between non-metal atoms
What is a molecule?
A fixed number (2 or more) of atoms covalently joined together
What is a compound?
A substance containing two or more different types of elements, chemically bonded together
Why do simple covalent molecular substances have low melting and boiling points?
Simple covalent molecular substances have low melting and boiling points because they have a simple covalent molecular structure containing strong covalent bonds due to strong electrostatic attractions between shared pairs of electrons and positive nuclei. However, this means that they have weak forces of attraction between molecules, so little heat energy is required to overcome the weak attractions between molecules.
Why are simple covalent molecular substances soft and brittle?
Weak forces of attraction between molecules can be overcome by a small amount of energy
Why can’t simple covalent molecular substances conduct electricity?
There are no mobile charge carriers (such as electrons) present as all the electrons in the outer shell are used in covalent bonds
Why does melting + boiling point increase as molecular mass increases?
- As molecular mass increases, melting and boiling point also increases
- this is because there are stronger forces of intermolecular attraction due to more electrons being in the atom, meaning that more energy is required to overcome this as you go down the group
Why are giant covalent lattices hard?
All the strong covalent bongs increase the rigidity of the structure and make it hard to break
Why do giant covalent substances have high melting and boiling points?
Giant covalent substances have high melting and boiling points as they have a giant covalent lattice structure in which each atom has strong covalent bonds due to strong electrostatic attractions between two positive nuclei and shared pairs of electrons. This means that lots of heat energy is required to break the many strong covalent bonds of the giant covalent lattice
What is the name overall name for things like diamond, graphite and C60 fullerene?
Allotropes of carbon
Which allotropes of carbon have giant covalent lattices and which have a simple covalent molecular structure?
Graphite and diamond have giant covalent lattice structures and C60 fullerene has a simple covalent molecular structure
Properties of diamond
- formula = C (giant ionic lattices have millions of atoms)
- each carbon makes 4 bonds creating a tetrehedral shape
- its one of the world’s hardest substances
- no mobile delocalised electrons so cannot conduct electricity
- won’t dissolve as it would involve breaking its strong covalent bonds
Properties of graphite
- each carbon atom makes 3 bonds creating hexagonal layers
- 4th electron is delocalised + mobile so can move around the whole layer (it has mobile charge carriers)= graphite conducts electricity
- doesn’t dissolve as that would involve breaking strong covalent bonds in its layers
- weak forces of attraction between layers mean that layers can easily slide off
- can be used as an industrial lubricant
Properties of C60 fullerene
- simple covalent molecular structure
- each carbon atom makes 1 double bond and 2 single bonds
- contains 60 carbon atoms in the spherical molecule
- SCM structure means that it has low melting and boiling point bc not much energy is required to overcome weak intermolecular forces
- also soft and brittle bc of SCM structure
- can’t conduct electricity as the delocalised electrons cannot move between molecules
What is metallic bonding?
The strong electrostatic attraction between layers of positive metal ions and the sea of mobile, delocalised electrons
What does metallic bonding occur between?
Metals only
Why do giant metallic lattice substances have high melting points?
Giant metallic substances have high melting and boiling points between they have giant metallic lattice structures contains strong metallic bonds bc of strong electrostatic attraction between positive metal ions and sea of electrons . This means that a lot of energy is required to break all the strong metallic bonds in the giant metallic lattice, giving them high melting and boiling points.
Why do metallic substances conduct electricity?
Metallic substances conduct electricity as there is a sea of mobile delocalised electrons which are free to move throughout the structure so therefore can carry a charge
Why are metallic substances malleable?
When a metal is hit, a layer of positive ions slide over. This doesn’t change the bonding structure as the sea of mobile delocalised electrons are free to move throughout the structure allowing the layers to slide without being repelled from each other, meaning that the shape and size of a metal can be changed without changing the bonding structure
Why can metallic substances conduct heat?
When a metal is heated, the delocalised electrons gain kinetic energy, moving faster and therefore transferring heat energy throughout the metal
