Part 2

• Groups have different numbers of electrons in their outer shell, which determines how they react chemically.
• How are elements arranged in a periodic table?

  In order of atomic number so that elements with similar properties are in groups.
• Prior to the discovery of sub atomic particles, how did scientists classify

  elements?

  In order of atomic weight.
• Explain why early periodic tables lacked discernible patterns.

  The early periodic tables were incomplete and some elements were placed in inappropriate groups if the order of atomic weights was followed
• How did Mendeleev overcome the problems of earlier periodic tables?

  By leaving gaps for elements that he thought had not been discovered and in some places changing the order of elements so they were in groups with similar chemical properties.
• Why was Mendeleev's table more acceptable than previous versions?

  Elements with properties predicted by Mendeleev were discovered and filled the gaps.
• Iodine and Tellurium were swapped by Mendeleev even though their weights were then in the wrong order. Why did he do that?

  So that they were placed in correct groups and their chemical properties matched the other elements in their new groups.
• ion

  An atom which has lost or gained an electron to become electrically charged
• What type of ions to metals form?

  Positive ions (cations).
• Why do positive ions form?

  Because the atom has lost electrons.
• What is oxidation?

  Loss of electrons.
• What type of ions do non-metals form?

  Negative ions (anions).
• Why do negative ions form?

  Because the atom has gained electrons.
• What is reduction?

  Gain of electrons.
• Why are group 0 elements called the noble gases?

  Because they have a complete outer electron shell and are inert.
• What does inert mean?

  Unreactive.
• How many electrons do group 0 elements have in their outer shell?

  Helium has 2, the rest have 8, this is why they are often more correctly called group 0 instead of group 8.
• Describe the trend in the boiling points of group 0 elements.

  They increase with increasing relative atomic mass (going down the group).
• What is the name of the Group 1 elements?

  Alkali metals.
• What do elements in group 1 have in common?

  All have 1 outer shell electron and similar chemical properties.
• What properties do group 1 metals have that are uncommon for metals?

  They are soft and can be easily cut with a knife. They react easily in air and water. The first 4 float on the surface of water.
• What properties do group 1 metals have that are common for metals?

  They are shiny when freshly cut. Good conductors of heat and electricity
• What product is formed when group 1 metals react with oxygen?

  Metal oxide.
• What is the general word equation for the reaction of group 1 metals with

  oxygen

  Metal + Oxygen --> Metal oxide
• What is the general balanced symbol equation for group 1 metals reacting

  with oxygen?

  4M + O2 --> 2M2O
• What product is formed when group 1 metals react with chlorine?

  Metal chloride
• What is the general word equation for the reaction of group 1 metals with

  chlorine?

  Metal + Chlorine --> Metal Chloride
• What is the general balanced symbol equation for group 1 metals reacting

  with chlorine?

  2M + Cl2 --> 2MCl
• What is the observation for the reaction of a group 1 metal with chlorine?

  Bright flame, white solid forms, green chlorine colour fades.
• What products are formed when group 1 metals react with water?

  Metal hydroxide + Hydrogen
• What is the general word equation for the reaction of group 1 metals with

  water?

  Metal + Water --> Metal Hydroxide + Hydrogen
• What is the general balanced symbol equation for group 1 metals reacting

  with water?

  2M + 2H2O --> 2MOH + H2
• What are the common observations for the reactions of the first 3 group 1

  metals with water?

  All float on the surface and move around.
• What are the unique observations for the reaction of lithium in water?

  It doesn't melt, it effervesces more slowly than the others.
• What are the unique observations for the reaction of sodium in water?

  It melts into a ball, it effervesces more quickly than lithium.
• What are the unique observations for the reaction of potassium in water?

  It melts into a ball, it burns with a lilac flame.
• Predict the unique observation for the reaction of caesium in water.

  It explodes.
• List the order of reactivity of the first three group 1 metals from least to most.

  Lithium, sodium, potassium.
• Why do the group 1 metals become more reactive as you go down the

  group?

  Their outer shell electron is further away from the positively charged nucleus. There is less attraction between the electron and the nucleus. It is easier to lose the outer shell electron.
• What is the name of the Group 7 elements?

  Halogens