Chemistry

• Which gas is released when the alkali metals react with water?

  Hydrogen
• Atoms lose electrons more easily down the group because there is a greater distance between the nucleus and the outer electron.


  group 1
• Which alkali metal is most reactive out of the following?

  potassium
• What is a mixture?

  It is made up of two or more substances mixed together but not chemically bonded
• What technique could be used to separate sand from water?

  Filtration
• The substance that has been dissolved into a liquid is called what?

  Solute
• Covalent bonding involves:


  sharing electrons
• An atom becomes an ion by:

  Gaining or losing electrons
• Electron that is free to move throughout a structure


  Delocalised electron
• Which alkali metal is the least reactive?

  Lithium
• A compound with a high melting point will have strong intermolecular forces between its molecules, which means it requires more energy to break these bonds. This results in a higher melting point.
• When two metals react together, their atoms lose electrons to form positive ions. When this happens, the metals join together to form a giant lattice structure held together by metallic bonds. Metallic bonds are formed when delocalised electrons are shared between all the metal ions within the lattice.
• Ionic compounds are soluble in water because they contain charged particles (ions) which can attract other oppositely charged particles (water molecules). The attraction causes the ions to become surrounded by water molecules forming hydrated ions. These hydrated ions then repel each other causing them to disperse through the solution.
• Reactivity decreases down the group.


  Group 7
• Ionic compounds are generally:


  hard with high melting and boiling points
• What is formed when sodium reacts with water?

  Sodium hydroxide and hydrogen
• The formula for magnesium oxide is MgO
• The formula for aluminum sulfate is Al2(SO4)3
• The formula for calcium carbonate is CaCO3