3A+Deanne

=Trends in the Periodic Table= =Boiling Points= By Deanne Blackburn In a liquid the molecules are packed closely together with many random movements possible as molecules slip past each other. As a liquid is heated, the temperature is increased. As the temperature increases, the kinetic energy increases which causes increasing molecular motion (vibrations and molecules slipping pas each other). Eventually the molecular motion becomes so intense that the forces of attraction between the molecules are disrupted to theextent the molecules break free of the liquid and become a gas. At the temperature of the boiling point, the liquid turns into a gas. The molecules are not in contact each other in the gaseous state.
 * Boiling Point Definition:**

The boiling point all depends on how much energy is needed to break the attractive forces and allow the particles to move freely and allow distance between them. So the stronger the attractive forces are, the more energy needed and hence the higher boiling point. When looking at the diagram above (boiling points) and the diagram to the below (main blocks of the periodic table). We see a trend in that all Lanthanide and Actinide series have h igh boiling points and majority of the transition metals, and most of the metals do as well. We can also see to the off centre left is where the highest boiling points do occur. -Silicon atoms is held together by strong covalent bonds - Needs a large amount of energy to break the bond -The Van Der Waals’ forces (Definition of Van Der Waals’ forces; the weak bonds between molecules, comprising dispersion forces, dipole-dipole forces and hydrogen bonding) that act between the molecules are broken when Phosphorus, Sulphur, Chlorine and Argon are boiling. -They have weak bonds, easy to br eak, therefore do not need much energy Out of the four, Sulphur has the highest boiling point as Sulphur is S₈ molecules, Phosphorus is P₄ molecules, Chlorine is Cl₂ molecules and Argon is Ar molecules. With the Van Der Waals’ forces strength, will decrease the size of the molecule decreases as well. With the boiling points decreasing in the order; Sulphur, Phosphorus, Chlorine then Argon.
 * What are the trends in Boiling Points? **
 * Silicon ** is an element that has some properties of metals and some properties of non-metals, therefore it is a metalloid. It has a lattice structure, because of covalent bonding and has a high boiling point because of;
 * Phosphorus, Sulphur, Chlorine and Argon ** are all non-metals with small separate molecules, with Argon a monatomic (separate atom) and Phosphorus, Sulphur and Chlorine have strong covalent bonds between the atoms because they are simple molecules. The boiling points are low, because;
 * Lithium, Sodium and Potassium** are all metals and has metallic bonding. When you boil metals, the metallic bond will be weakened and then broken when you completely boil the metal. Hence the boiling point reflects the strength of the metallic bond.

Overall the trends in boiling points in the periodic table all depends on what type of bond the molecule has and what group it is in. As non-metalshave weak bonds, they are easy to break so they have low boiling points. As for metals, they have high boiling points because more energy is needed to break their stronger bonds. The picture below shows as which periods and groups have the highest and the lowest boiling points, and helps us associate them with trends.

Thank you for reading and please comment :)