Bonding Flashcards
What elements form a ionic bond
Metal and non-metal
What happens is ionic bonding
-the metal loses electrons to form a positively charged ion
-the non-metals gain these electrons to form a negatively charged ion
-these oppositely charged ions are strongly attracted due to electrostatic forces
What are positive ions called
Cations
What are negative ions called
Anions
What elements form a covalent bond
Non-metals
What structure do ionic compounds have
-A giant ionic lattice
-the ions have strings electrostatic forces of attraction in all directions in the lattice
Properties of ionic compounds
-high … and boiling …
->a lot of … is needed to … the … of attraction
-when … can’t … electricity
-when … can conduct … because the … are … to move so can … electric …
-some … in …
-high melting and boiling points
->a lot of energy is needed to overcome the forces of attraction
-when solid can’t conduct electricity
-when liquid can conduct electricity because the ions are free to move so can carry electric charge
-some dissolve in water
What happens in covalent bonding
-atoms only share electrons in their outer shells (highest energy levels)
-each covalent bond provides an extra shared electron for each atom
-there are enough covalent bonds to fill up the outer shell making it stable
What are the different ways of drawing bonds
-dot and cross diagram, uses o ans x
-displayed formulas, where u write the symbol and draw straight lines between them eg Cl-Cl
Properties of covalent bonds
-have very strong … forces of … with the … in a molecule
-weak … forces of … between the …
-… melting and … point
-mainly … or gases at … temp
-as the … gets … the intermolecular … become …
-… conduct … as there are no free …
-have very strong electrostatic forces of attraction with the atoms in a molecule
-weak intermolecular forces of attraction between the molecules
-low melting and boiling points
-mainly liquids or gases at room temp
-as the molecule gets bigger the intermolecular forces become stronger
-don’t conduct electricity as there are no free electrons
What are giant covalent structures
Macromolecules
What happens in giant covalent structures
All the atoms are bonded to eachother by string covalent bonds
Properties of giant covalent structures
-very high melting and boiling points
-don’t conduct electricity
Examples of giant covalent structures
-diamond
-graphite
-silicon dioxide
Structure of diamond, graphite and silicon dioxide
Diamond:
-each … atom forms … covalent … in a … structure
Graphite:
-each carbon atom forms … covalent … to create layers of …, each … atom has 1 … electron
Silicon dioxide:
-made of … and oxygen
Diamond:
-each carbon in atom forms 4 covalent bonds in a rigid structure
Graphite:
-each carbon atom forms 3 covalent bonds to create layers of hexagons, each carbon atom has 1 delocalised electron
Silicon dioxide:
-made of silicon and oxygen
Why is diamond very hard
-is a giant covalent structure
-made up of carbon atoms that each form 4 covalent bonds
-this makes diamond very hard
Why does diamond have a very high melting point
-it’s a giant covalent structure
-made up of carbon atoms that each form 4 covalent bonds
-the covalent bonds take a lot of energy to overcome
Why does diamond not conduct electricity
-as each carbon atom forms 4 covalent bonds
-it has no free electrons or ions
-so no electricity can be transported throughout the material
Why is graphite soft, slippery and a good lubricant
-each carbon atom forms only 3 covalent bonds
-there are no covalent bonds between layers
-so they are free to move over eachother
Why does graphite have a high melting point
-the covalent bonds in the layers require a lot of energy to overcome
Why can graphite conduct electricity
-only three out of carbons 4 outer shell electrons are in a covalent bond
-each carbon atom as one delocalised electron
-these electrons can carry electrify through the layers
What is graphene
-… layer of …
-it is … atom … and is two-…
-it is very …
-has … covalent …
-can conduct …
-one layer of graphite
-it is one atom thick and is two-dimensional
-it is very light
-has strong covalent bonds
-can conduct electricity
What are fullerenes
-molecules of … shaped like closed … or … balls
-they are mainly made up of … atoms arranged in …, pentagons or h…
-molecules of carbon shaped like closed tubes or hollow balls
-they are mainly made up of carbon atoms arranged in hexagons, pentagons or heptagons
What atoms are fullerenes made of
Carbon atoms
What are fullerenes used for
-to … other …
-the fullerene … forms … another atom or … which becomes …
—>this can be used to … a …
-they have a huge … area so are good …
-also good l…
-to cage other molecules
-the fullerene structure forms around another atom or molecule which becomes trapped
—>this can be used to deliver a drug
-they have a huge surface area so are good catalysts
-also good lubricants
What can fullerenes form
Nanotubes
What is a nanotube
-tiny … cylinders formed from …
-… between … and … is very …
-can conduct … and …
-high … strength (… break when …)
-used in …
-tiny carbon cylinders formed from fullerenes
-ratio between length and diameter is very high
-can conduct heat and electricity
-high tensile strength (don’t break when stretched)
-used in nanotechnology
What are the electrons on the outer shell of metal atoms in metallic bonding
Delocalised
Why is metallic bonding very strong
-There are strong … forces of … between the … metal ions and the … negative …
-these … hold atoms together in … bonding
-these forces require a lot of … to …
-There are strong electrostatic forces of attraction between the positive metal ions and the shared negative electrons
-these forces hold atoms together in metallic bonding
-these forces require a lot of energy to overcome
What substances are held together by metallic bonding
-m… e…
-a…
-metallic elements
-alloys
What are most metals solid at room temp
-… have … bonding
-the … forces between the … atoms and … sea of … are very … so need lots of … to …
-this means they have a … melting and … point so are generally …
-metals have metallic bonding
-the electrostatic forces between the metal atoms and delocalised sea of electrons are very strong so need lots of energy to overcome
-this means they have a high melting and boiling point so are generally solids
Why are metals good conductors
-the delocalised electrons carry electric charge and thermal energy through the whole structure
Why are most metals malleable
-the layers of atoms can slide over eachother
Why are alloys harder than pure metals
-… metals are often too … when …
-so they are … with other … to make them …
-… are a mixture of … or more metals, or metals and …-metals
-different … have different sized … so when an element is … with a … metal the … become …
-making its more … for them to … over …
-this means they are …
-pure metals are often too soft when pure
-so they are mixed with other metals to make them harder
-alloys are a mixture of 2 or more metals, or metals and non-metals
-different elements have different sized atoms so when an element is mixed with a pure metal the layers become distorted
-making its more difficult for them to slide over eachother
-this means they are harder
What is an alloy
A mixture of 2 or more metals, or a mixture of metals and non-metals
