ionic, covalent, metallic bonding Flashcards
when do simple ions form?
when atoms lose or gain electrons
what are ions?
An ion is an electrically charged atom or group of atoms formed by the loss or gain of electrons.
when is an atom positively or negatively charged? what is another name for these
positive-loss of electrons
negative-gain electrons
cations, anions
what is the number of electrons lost or gained the same as?
the charge on the ion e.g., 2 electrons lost then the charge is 2+
what do metals form?
groups 1,2,3 are metals and they lose electrons to form positive ions
what do non metals form?
groups 5,6,7 are non metals and they gain electrons to form anions
what is the charge of Ag?
Ag+
what is the charge of Fe?
Fe2+ or Fe 3+
what is the charge of Cu?
Cu2+
what is the charge of Pb?
Pb2+
what is the charge of Zn?
Zn2+
what is the charge of H2?
H+
what is the charge of hydroxide?
OH-
what is the charge of Ammonium?
NH4. + (4 is subscribt)
what is the charge of carbonate?
CO3. 2-
what is the charge of nitrate?
NO3 -
what is the charge of sulphate?
SO4. 2-
what does a transfer of electrons produce?
a transfer of electrons produces an ionic compound. This is because when a nonmetal and a metal react together, and their opposite charges (as they are charged ions) strongly attract to one another by electrostatic attraction. they form an ionic bond
what is the force between two charged ions
electrostatic attraction
how is ionic bonding often depicted?
using dot and cross diagrams
(the ones with the diagram showing where the electron goes and then brackets around each ion)
what are compounds always?
electrically neutral
what is the difference between the ending ‘ide’ and ‘ate’
ide just means that it is what is described. e.g., copper sulfide it just copper and sulfate
however ate means that oxygen is present
what od all ionic compounds form?
crystals
what do ionic crystals consist of?
a lattice of positive and negative ions packed together in a regular way.
what is a lattice?
a regular array of particles. it is held together by strong electrostatic attractions between positively and negatively charged ions
how would you draw a giant ionic lattice?
like a cube but w only the atoms
look this up or look at p 82 or textbook
what are some chemical/physical properties of ionic compounds? - BP and MP
- high melting and boiling points because of the electrostatic attractions holding the lattice together, therefore a lot of energy has to be supplied in order to separate them
- ionic compounds tend to be crystalline, this reflects the regular arrangement of ions in the lattice
- ionic crystals tend to be brittle - this is because any small distortion of a crystal will bring ions with the same charge alongside each other. like charges repel and so the crystal splits itself apart
- ionic substances tend to be soluble in water
- ionic compounds tend to be insoluble in organic solvents
why do ionic crystals tend to be brittle
ionic crystals tend to be brittle - this is because any small distortion of a crystal will bring ions with the same charge alongside each other. like charges repel and so the crystal splits itself apart
do ionic compounds conduct electricity?
they conduct electricity when they are molten or it they are dissolved in water (an aqueous solution). This happens because the IONS then become free to move around.
they don’t conduct electricity when they are solid because the IONS are fixed in position and are not free to move around
what do compounds with ionic bonding always have? why and how?
giant ionic structures, they are held together in a closely packed 3D lattice arrangement by the attraction of oppositely charged ions.
this electrostatic attraction between oppositely charged ions are very strong because a lot of energy is needed to overcome the strong attraction
what is the relationship between particles in any bond?
they are held together by electrostatic attractions between something positively charged and something negatively charged
what is a covalent bond?
a covalent bond is where a pair of electrons is shared between two atoms. what holds the atoms together is the strong electrostatic attraction between the nuclei (positively charged) of the atoms that make up the bond, and the shared pair of electrons (negatively charged)
what happens when a bond of any kind is made?
energy is released, and that makes the things involved more stable than they were before.
The more bonds an atom can form, the more energy is released and the ore stable the system becomes
what does double bonding look like? give an example.
an oxygen has 6 atoms in its outer shell so they dorm a double bond because 2 electrons form a bond with 2 other electrons
draw what a double and tripple bond looks like in both writing and dot and cross
check p 90 for reference
draw the dot and cross and symbol (showing the bond) for ethene, co2, nitrogen
check p 90 for reference
draw the dot and cross for chloroethene
p 91
water is made up of covalent bonds. . the h and o atoms are joined by covalent bonds. but what is the force called between the molecules?
intermolecular forces
what are intermolecular forces?
intermolecular forces are the attractive or repulsive forces that exist between molecules.
(including the electromagnetic forces of attraction or repulsion between atoms and other neighboring particles)
what are intramolecular forces?
Intramolecular forces are the forces that hold atoms together within a molecule
what is the name of a (covalent substance) that consists of molecules with intermolecular forces? give examples
simple molecular structure
e.g., water, carbon dioxide, CH4, C2H4
what do substances with simple molecular substances tend to be?
gases or liquids with low melting and boiling points
are intermolecular forces stronger or weaker than covalent bonds?
weaker.
what does MP and BP increase with often (in group 7!)
RAM. this means that the intermolecular force of attraction must be stronger as relative molecular mass increases
do covalent molecular compounds conduct electricity? why?
no. this is because the molecules don’t have an overall electrical charge as there are no ions and all the electrons are held tightly in the atoms or in covalent bonds so are not able to move from molecule to molecule
what are some trends for covalent moecular substances
covalent molecular substances are insoluble in water - there are some exceptions including ethanol, hydrochloric acid
covalent molecular substances are often soluble in organic solvents
why do simple molecular structures have low melting and boiling points + are gases or liquids?
imple molecular structures have low melting and boiling points because the weak intermolecular forces between their molecules require little energy to overcome.
Simple molecular structures are often gases or liquids at room temperature because the intermolecular forces between the molecules are weak and easy to overcome
name some forms of carbon
diamonds, graphite, (buckminster) fullerine
describe everything you can about diamond
- each carbon atom has 4 electrons in its outershell, therefore forms 4 covalent bonds
- it has a tetrahedral arrangement (draw this out)
- it is a giant covalent structure
- it is NOT a molecule as molecules always contain fixed number of atoms joined by covalent bonds but real diamonds are much more complex
- very high melting and boiling points because of the strong carbon-carbon covalent bonds
- there are no intermolecular forces because it is not a molecule. therefore covalent bonds must be broken to melt or boil it
- Diamond is very hard ( a lot of energy must be supplied otherwise break the strong covalent bonds throughout the structure)
- it doesn’t conduct electricity because the electrons in the outer shells of the carbon atoms are held tightly in covalent bonds between the atoms and none are free to move around
what structure and arrangement does diamond have?
it has a tetrahedral arrangement
it is a giant covalent structure
- it is NOT a molecule as molecules always contain fixed number of atoms joined by covalent bonds but real diamonds are much more complex
what is the boiling/melting point of diamond? why? does it conduct electricity? is it soft or hard?
- very high melting and boiling points because of the strong carbon-carbon covalent bonds
- there are no intermolecular forces because it is not a molecule. therefore covalent bonds must be broken to melt or boil it
- Diamond is very hard ( a lot of energy must be supplied otherwise break the strong covalent bonds throughout the structure)
- it doesn’t conduct electricity because the electrons in the outer shells of the carbon atoms are held tightly in covalent bonds between the atoms and none are free to move around
describe everything you know about graphite
- it is a giant structure
- it has a layer structure
- it is a soft material (although the forces holding the atoms together in each layer are strong, the attraction between the layers are much weaker, and not much energy is needed to overcome them. layers slide over each other and can easily be flaked off)
- high melting and boiling point (covalent bonds must be broken = high level of energy)
- conducts electricity
- each carbon atom is joined to 3 other carbon atom
- this means that there is a fourth electron in each outer shell that is free to move throughout the layers. these are delocalized electrons. the movement of these electrons allows graphite to conduct electricity)
Can graphite conduct electricity? explain your answer
yes
each carbon atom is joined to 3 other carbon atom
- this means that there is a fourth electron in each outer shell that is free to move throughout the layers. these are delocalized electrons. the movement of these electrons allows graphite to conduct electricity)
describe the arrangement, structure, and harness of grpahite.
it is a giant structure
- it has a layer structure
- it is a soft material (although the forces holding the atoms together in each layer are strong, the attraction between the layers are much weaker, and not much energy is needed to overcome them. layers slide over each other and can easily be flaked off)
what is the boiling/melting point of graphite.
- high melting and boiling point (covalent bonds must be broken = high level of energy)
what is an allotrope? give examples
different forms of the same element.
allotropes of carbon include: diamond, fullerene, graphite
describe everything you know about (buckminster) fullerene
- simple molecular structure
- in solid or liquid buckminsterfullerene, there are molecules with weak intermolecular forces between them
- this means it has a lower melting and boiling point than diamond and graphite (not a lot of energy is required to break the bones)
- not as hard as diamond - it does not take as much energy to break intermolecular forces of attraction compared to covalent bonds of diamonds
- doesn’t conduct electricity. even though the carbon atoms only form 3 bonds, the fourth electron on each atom can only move around withing each Buckminster fullerene molecule and so the electrons can not jump from molecule to molecule
what is Buckminster fullerene also known as?
C60 fullerene because a fullerene with the formula C60 is made up of 60 carbon atoms arranged in a spherical shape
describe the boiling and melting point + hardness of B-fullerene
in solid or liquid buckminsterfullerene, there are molecules with weak intermolecular forces between them
- this means it has a lower melting and boiling point than diamond and graphite (not a lot of energy is required to break the bones)
- not as hard as diamond - it does not take as much energy to break intermolecular forces of attraction compared to covalent bonds of diamonds
does B-fullerene conduct electricity?
- doesn’t conduct electricity. even though the carbon atoms only form 3 bonds, the fourth electron on each atom can only move around within each Buckminster fullerene molecule and so the electrons can not jump from molecule to molecule
what type of structure does Buckminster fullerene have?
simple molecular structure
do covalent compounds usually conduct electricity?
no
what is a molecule?
Two or more atoms joined together by covalent bonds (sharing electrons)
describe the different bonds in covalent structures
- the atoms within the molecule have strong covalent bonds
- the forces of attraction (intermolecular forces) between the molecules are very weak
this means that they can be easily separates (low melting and boiling points)
why are intermolecular forces stronger between molecules with a higher Mr? (covalent)
this is because there are more points along the larger molecules for intermolecular forces to act between, so more energy is required to break these forces
what is a giant covalent structure vs a simple molecular substance?
Giant covalent structures are made up of many non-metal atoms that are bonded together in a giant lattice. The atoms are arranged in a fixed ratio and are joined by strong covalent bonds.
a simple molecular substance is a substance made up of a group of atoms held together by covalent bonds, but with weak intermolecular forces between the molecules
why do giant covalent structures have high melting and boiling points?
all the atoms are bonded to each other by strong covalent bonds. there are lots of these bonds which means it takes a lot of energy to break them
do giant covalent structures conduct electricity? why?
no not even when molten
Most substances with giant covalent structures have no charged particles that are free to move.
what are some other properties of giant covalent structures?
- usually insoluble in water
- high melting and boiling point
- do not conduct electricity
- strong covalent bonds
- no charged ions
what is a covalent bond in terms of electrostatic attractions
a covalent bond is an electrostatic attraction between the positively charged nuclei of two atoms and the negatively charged electrons they share
what is an ionic bond in terms of electrostatic attractions
The ionic bond is the electrostatic force of attraction between a positively charged metal ion and a negatively charged non-metal ion.
what is electric current?
flow or electrons or ions
what charge do electrons have?
negative charge
what charge do ions have
positive or negative
what makes a material conduct electricity? why?
when electrons or ions move. the electric current is the flow of electrons or ions
when do ionic compounds conduct electricity? why?
only when molten or in a solution.
They are made of a lattice of positive and negative ions. Solid ionic compounds can conduct electricity because these ions can’t move around. However, they can if the ionic compound is melted or it is dissolved
what are metals held together by?
metallic bonding
describe the structure of metals.
they have a giant structure of positive ions surrounded by a sea of delocalised electrons.
the electrostatic attractions between the nuclei of positive ions and electrons are called metallic bonding
how do metals get their properties
the metallic bonding
name some properties of metal. why do they have these properties?
- good conductors of electricity and heat
- good conductors of heat
- malleable because the layers of ions in a metal can slide over each other, making them malleable
- this is because the delocalised electrons are able to move through the structure and electric current is the flow of electrons or ions
- the movement of these electrons also means energy can be transferred quickly through the material, so metals are good conductors of hear
what happens when sodium atoms bond?
they form sodium metal. the outer electron is free to move around throughout the whole structure to there is a sea of delocalised electrons
what does a metallic structure consist of?
it consists of a lattice (regular arrangement) of positive ions in a sea of delocalised electrons
what is metallic bonding?
the electrostatic forces of attraction between each positive ion and delocalised electron. this holds the structure together
What type of structures do metals have?
a giant structure. this means that there are no individual molecules and all the positive ions in the lattice attract delocalised electrons
what does the fact that metals are hard and have high melting and boiling points suggest?
that the electrostatic forces of attraction between the positive ions and the delocalised electrons are strong
why do metals conduct electicity?q
the delocalised electrons are free to move throughout the structure
what does it mean if a metal is malleable?
when force is applied to a metal, the layers of positive ions slide over each other
what does it mean if a metal is ductile?
it means a metal can be drawn out into a wire. this is because the positive ions can slide over each other
draw out a metallic lattice by a 2-D diagram
what is a metallicbond in terms of electrostatic attractions
the electrostatic force of attraction between positively charged metal ions and delocalized electrons
