The Periodic Table

• How are elements ordered?


  Their increasing atomic number
• What does an elements group number signify?


  The number of electrons on the outer shell.
• What does an elements period number signify?


  THe number of highest energy electron shell.
• How many electrons can fit the s subshell?

  2
• How many electrons can fit in the p subshell?


  6
• How many electrons can fit the d subshell?

  10
• Does the 3d subshell come first?


  No as it has a higher energy level than the 4s subshel.
• How are energy shells filled up?


  The s subshell is filled up first and then the p subshell.
• What happened to the atomic radius as you move across a period?


  It decreases.
• Why does the atomic radius decrease as you move across a period?

  There is one more proton in its nucleus.The positive charge therefore increases so there is a positive attraction between the nucleus and the electrons.
• Is shielding the same across a period?


  Yes as there are the same number of shells.
• What happenes to the atomic radius as you go down a group?


  It increases.
• Why does the atomic radius increase as you go down a group?


  The number of electron shells increases, so the outer shell is further awany from the nucleus. Nucleus charge does not have an affect.
• What happenes to the effects of shielding as you go down a group?


  It increases as there is one full inner electron so there is a weaker attraction.
• What is the trend in boiling point for Na,Mg and Al?

  Metallic bonding gets stronger ,the more electrons there are in the outer shell that are released o the sea of electrons. A smaller sized ion with a greater positive charge also makes the bonding stronger so higher energy is neede to break metallic bonds.
• What is the melting and boiling point of Si?

  Si is macromolecular so it contains many strong covalent bonds between atoms high energy needed to break covalent bonds so they have a high melting and boiling point.
• What is the melting and boiling point of Cl2,S8 and P4?

  They have weak London forces between molecules due to the simple molecular bonding so little energy is needed to break them.
• Why does S8 have a higher melting point than P4?

  S8 has more electrons so has stronger London forces between molecules.