As you go down group 1 (the alkali metals) the melting point decreases as the atomic radius increases.[1] For example Lithium has an electronic configuration of 2,1 so it only has two shells so there are stronger forces of attraction between the shells which means more energy is required to break these forces. Whereas, Potassium has an electronic configuration of 2,8,8,1 thus it has 4 shells, therefore there is less force of attraction between the shells which means there is less energy required to break these forces of attraction between the shells.
The closer each lone electron on the outer shell of each atom is to the inside nucleus of an atom; the stronger the attraction. So the more closely bond the atom, the less reactive the element is. When the atomic radii is low, there needs to be more energy applied in order to break the lone electron on the outer shell from the nucleus. This also explains why the atomic number (this is just a way of discribing the atomic radii- the smaller the atomic number the smaller it's atomic radii) affects boiling and melting point – more heat energy has to be applied to elements with the lower boiling/meting points because there are stronger forces between the atoms so more heat needs to be applied to break the bonds and change the element from a solid to a liquid; a liquid to a gas. The higher the atomic number the more reactive the element is, based upon this principle. I know this rambles on, but I hope it's been helpful to you.
Acctually, the 5th guy down got it right. And neutrons don't have a charge, so the nucleus is posative, and electrons are negative. Atoms can have more neutrons than protons - thats what isotopes are, and radioactive materials that produce alpha radiation - such as Francium - throw out neutrons to try and stabalize themselves. Besides, this is a very reliable source for coursework anyway.
As you go down a column in the periodic table, the atomic radius descreases, and melting point dramatically decreases for the alkali metals. However, for other groups, this is not the case, and the trend is fairly complex and irregular. Except from Silver and Calcium.
All of the above answers arn't completely correct so if your doing course work don't use these answers as there is no such thing as a positively charged nucleus as a nucleus as an equal amount of neutrons and protons
I think...as atomic radius increases so does melting point. This is because as the space between the nucleus and the outer shell increase..the electrons are less firmly held and so less energy is needed to separate them
As atomic radius increases the boiling point decreases, because as the space between the nucleus and the outer shell increase..the electrons are less firmly held and so less energy is needed to separate them.
