Q2

• True or false? Simple molecular substances contain delocalised electrons.

  false
• What type of bonds do compounds formed from non-metals consist of?

  covalent
• Biodegradable plastic bags are now being made from polymers and what other substance?

  constarch/starch
• In which of the 3 states of matter are the particles close together and moving randomly?

  liquid
• True of False?

  If an element can form covalent bonds then it will never be involved in ionic bonding

  False

  Non-metals can form ionic bonds with metals, but can form covalent bonds with other non-metals.
• Oppositely charged ions in an ionic compound are held together by ___ forces

  electrostatic
• A liquid consists of simple molecules. Are the forces within the molecules strong or weak?

  Strong

  the atoms WITHIN molecules are held together by covalent bonds, which are strong.
• An unknown substance has a melting point of -77C. Is this substance likely to be an ionic compound

  No

  Ionic compounds have high melting points.
• Calcium oxide is an ionic compound. Predict its physical state (solid, liquid, gas) at room temp

  Solid

  Ionic compounds have high melting points.
• True OR False?

  In graphite , every atom forms strong bonds with four other atoms.

  False

  In graphite, each carbon atom is strongly bonded to three other atoms.
• What name is given to a substance made from a mixture of two or more different metals?

  alloy
• Which tend to be harder, pure metals or alloys?

  Alloys

  Alloys are harder because the different sized atoms distort the layers and make it less easy for the layers to slide over each other.
• Which part of their structure do metals have in common with graphite that means both substances conduct electricity?

  Delocalised electrons

  Both substances contain delocalised electrons, which can move through the structure and carry charge.
• Which state of matter has no definite volume or shape?

  gas
• Which type of atomic forces hold ionic compounds together?

  Electrostatic
• What is the name given to the temperature when a liquid turns into a gas?

  boiling(point)
• Oxygen is a non-metal in group 6. This tells us that it will produce ions that have a charge of ___.

  -2

  Group 6 elements gain 2 electrons to form 2- ions.
• What type of bond links the atoms together in an polymer molecule?

  Covalent

  The atoms in polymers are non-metals, so they are held together by covalent bonds.
• Are the bonds between the atoms in a polymer weak or strong?

  strong
• A single layer of graphite is called a ___?

  graphene
• How many atoms thick is graphene?

  1