How does the melting point of elements vary across thegroups?

Answer 1

Melting point trends on the Periodic Table can be understood in a crude way using the following rule of thumb: The stronger the forces that act between molecules of a substance, the higher the melting point tends to be.

The trends are very complex because many different factors influence the forces between atoms (or molecules) in an element. Notice that for each period beyond the first, the melting point rises to a maximum somewhere around the middle of the period and then falls off to a minimum value at the end of the period.

The melting points of the first period elements are extremely low, because forces between H2 molecules and between helium atoms are exceptionally weak.

In the second period, there is a gradual transition from relatively weak metallic bonding in lithium to strong network covalent bonding in carbon. Nitrogen, oxygen, and fluorine also form strong covalent bonds but they can't form networks of bonds the way carbon does. Atoms of these elements pair up to form diatomic molecules. While the attractive forces within atoms in the diatomic gas molecules is strong, the forces between molecules is very weak. That causes the sharp dropoff in melting point after carbon in the second period.

The trend is repeated in a more subdued way in the third period. There is a jump in melting point from aluminum to silicon where bonding changes from primarily metallic to more covalent. P and S are better able to link into chains and rings than their second period counterparts, and have much higher melting points than N2 and O2. In the fourth period, the rise and fall of melting points across the period is even more muted. Note the discontinuity going from gallium (Ga) to germanium (Ge) at the metal/metalloid border.

Answer 2

Melting point trends on the periodic table can be understood in a crude way using the following rule of thumb: The stronger the forces that act between molecules of a substance, the higher the melting point tends to be.

The trends are very complex because many different factors influence the forces between atoms (or molecules) in an element. Notice that for each period beyond the first, the melting point rises to a maximum somewhere around the middle of the period and then falls off to a minimum value at the end of the period.

The melting points of the first period elements are extremely low, because forces between H2 molecules and between helium atoms are exceptionally weak.

In the second period, there is a gradual transition from relatively weak metallic bonding in lithium to strong network covalent bonding in carbon. Nitrogen, oxygen, and fluorine also form strong covalent bonds but they can't form networks of bonds the way carbon does. Atoms of these elements pair up to form diatomic molecules. While the attractive forces within atoms in the diatomic gas molecules is strong, the forces between molecules is very weak. That causes the sharp dropoff in melting point after carbon in the second period.

The trend is repeated in a more subdued way in the third period. There is a jump in melting point from aluminum to silicon where bonding changes from primarily metallic to more covalent. P and S are better able to link into chains and rings than their second period counterparts, and have much higher melting points than N2 and O2. In the fourth period, the rise and fall of melting points across the period is even more muted. Note the discontinuity going from gallium (Ga) to germanium (Ge) at the metal/metalloid border.

I hope this helps =D

Answer 3

The melting and boiling points increase across the period until the metalloids (blue block on the above diagram) and then decrease.

The correct answer is decreases.

Answer 4

Melting and boiling points increase from a relatively high value in Group I across a period up to Group IV and then decrease dramatically to Group 0. This is because the forces between particles in a metal are srong, in the Group IV elements extremely strong, but weak in the non-metals.

Thus, the metals in Groups I & II have much higher melting/boiling points than the non-metals in Groups VI and VII; and the Group IV elements have the highest values of all.

JJR

Answer 5

it useally goes higher across the period but down a group im not sure, p block low melting points and d block have high melting points, i hope im makeing sense

Answer 6

As you move down a group (column) metals tend to have similar properties (melting point, electrical resistance, etc.)

Answer 7

• they de-crease,
• Thanks
• LOL!
• :)

Answer 8

Generally, it decreases.

Answer 9

i im in 9 grade ok