C2.1 + 2 Structure and Bonding + Structure and Properties Flashcards
(46 cards)
What is the mass number?
Total number of protons and neutrons of an atom
<p>What is the atomic number?</p>
<p>Total number of protons/electrons</p>
<p>Define a 'compound'.</p>
<p>Substances in which atoms of two or more elements are chemically combined</p>
<p>Define an 'isotope'.</p>
<p>Different atomic forms of the same elements, with the same atomic number but a different number of neutrons.</p>
<p>Name two isotopes of carbon.</p>
<p>Carbon-12 and Carbon-14</p>
<p>What is an ionic bond?</p>
<p>A bond formed between metals and non-metals</p>
<p>Describe how an ionic bond happens.</p>
<p>- The metal loses its electrons and becomes positively charged
- The non-metal gains those electons and become negatively charged.
- The positive metal ion and negative non-metal ion are attracted to each other and the compound is ionically bonded</p>
<p>Why do atoms bond?</p>
<p>To gain a full outer shell and become energetically stable</p>
<p>What group in the periodic table has a full outer shell?</p>
<p>Group 0 - the noble gases</p>
<p>How do Group 1 elements react with non-metals?</p>
<p>The alkali metals (group 1) only have one electron in their outer shell. They lose this electron to have a full outer shell and become a metal ion with a single positive charge</p>
<p>How do Group 7 elements react with metals?</p>
<p>The halogens (group 7) have 7 electrons in their outer shell. They gain another electron from a metal to have a full outer shell and become halide ions with a single negative charge. </p>
<p>Describe the structure of an ionic compound.</p>
<p>- They form giant ionic lattices
| - There are strong forces of electrostatic attraction between oppositely charged ions </p>
<p>Describe and explain the properties of giant ionic compounds. </p>
<p>- High melting points = strong forces of electrostatic attraction between the ions that take a high amount of energy to overcome.
- Conductors of electricity when molten = the ions are free to move and can carry electric current.
- Conductors of electricity when dissolved in water = the ions separate and are free to move and carry current</p>
<p>What carries electric current?</p>
<p>Moving electrons/ions</p>
<p>Work out the ionic formula of sodium chloride.</p>
<p>- Sodium chloride contains Na (1+) and Cl (1-)
- Swap over the charge numbers (here it's sort of pointless but whatever) Na1 and Cl1.
- Formula = NaCl (metal always goes first)</p>
<p>Work out the ionic formula of magnesium chloride.</p>
<p>- Magnesium chloride contains Mg (2+) and Cl (1-)
- Swap over the charge numbers so Mg1Cl2
- Formula = MgCl2 (small numbers)</p>
<p>What are the two types of covalent bonding?</p>
<p>- Simple molecular covalent bonding
| - Giant covalent structures</p>
<p>Describe the bonds between simple molecular substances.</p>
<p>- The atoms form very strong covalent bonds to form small molecules
- However, the intermolecular forces are very weak</p>
<p>Describe and explain the properties of simple molecular substances.</p>
<p>- They have low melting/boiling points as the weak intermolecular forces are easy to break.
- They are usually gases/liquid at room temperature
- They don't conduct electricity as there are no ions so no electrical charge.</p>
<p>Name 3 examples of simple molecular substances</p>
<p>- Water
- Oxygen
- Chlorine</p>
<p>Give three examples of substances of giant covalent structures. </p>
<p>- Diamond
- Graphite
- Silicon dioxide</p>
<p>Describe and explain the properties of diamond.</p>
<p>- Each carbon atom forms four covalent bonds in a tight rigid structure so it is very hard.
- It doesn't conduct electricity as there are no free electrons and no ions.
- It has a very high melting point as there are strong covalent bonds between the atoms with strong intermolecular forces
- It is insoluble as its covalent bonds are stronger than the H20 bonds so they can't be hydrated. </p>
<p>Describe and explain the properties of silicon dioxide.</p>
<p>- Each silicon atom forms four covalent bonds in a tight rigid structure so it is very hard.
- It has a very high melting point as there are strong covalent bonds between the atoms with strong intermolecular forces.
- It is insoluble as its covalent bonds are stronger than the H20 bonds so they can't be hydrated. </p>
<p>Describe and explain the properties of graphite.</p>
<p>- It is soft and slippery as each carbon atom only forms three covalent bonds, creating layers which are free to slide over each other. The layers only have weak intermolecular forces between them making it easier for them to slide across each other.
- It is a good conductor of heat and electricity (the only non-metal). Each carbon atom has a delocalised electron which can move and carry electrical charge. </p>
Describe the structure of metallic structures.
They are giant structures of atoms arranged in a regular pattern. Delocalised electrons hold the atoms together in this structure as there are strong forces of electrostatic attraction between the positive metal ions and the negative electrons.
Draw a giant ionic lattice.
Draw a metallic structure
