Summer Assessment 3

Number of protons and neutrons

-subtract atomic number from mass number

Number of protons

-groups of atoms

• Vertical column in the Periodic Table - All elements in the same group have the same number of outer shell electrons and similar chemical properties.

Unreactive

-Horizontal row in the Periodic Table

Group 0

• inert - colourless gases

-don’t have a full outer shell of electrons so arent desperate to give up/ gain electrons

-a positively charged part and a negatively charged part

• always have giant ionic structure • ions held in closely packed 3D lattice arrangement • electrostatic attraction between oppositely charged ions is very strong • due to lots of energy needed to overcome the strong attraction- high melting and boiling point • not electrical conductors when solid but are if melted/ dissolved in water

• atoms within molecule held together by very strong covalent bonds • the forces of attraction between molecules = very weak • this results in a low melting and boiling point as molecules are easily spereated • most are gases or liquids at room temperature

melting and boiling point increases as relative molecular mass increases

• atoms are bonded to each other by strong covalent bonds • lots of these bonds- lots of energy to break them- high melting and boiling point • don’t conduct electricity- not even when molten` • usually insoluble in water

• its made up of a network of carbon atoms that each form 4 fcovalent bonds • strong covalent bonds take lots of energy to break so diamond has high melting point • strong covalent bonds hold atoms in very rigid lattic structure so its really hard • doesnt conduct electricity as it has no free electrons or ions

• each carbon atom only forms 3 covalent bonds creating layers of carbon atoms • layers are held together by weak intermolecular forces of attraction- so can slide over each other- making graphite soft and slippery • high melting point- covalent bonds in layers need lots of energy to break • graphite has one delocalised electrong which is free to move- so it can conduct electricity

• hard • high melting point • high boiling point • cant conduct electricity

• soft and slippery • high melting point • conducts electricity

• made up of large covalent molecules • molecules held together by intermolecular forces that can slide over each other- hence why material is soft • each carbon in C60 fullerene has a delocalised electron- however electrons cannot move between molecules so C60 fullerene is a poor conductor of electricity

• soft - poor conductor of electricity

• electric current = flow of electrons or ions - when electrons/ ions move they cause material they are in to conduct electricity

• as solid ionic compounds dont conduct electricity as ions cannot move around • however when ionic compounds are dissolved, ions are seperate and able to move so can conduct electricity • when ionic compound melts- ions are able to move- so ions can conduct electricity

-metallic bonding