We normally associate metals with solids (at room temperature) -- mercury being one exception. All materials, solids or fluids, can conduct heat. However, not all solids are good conductors, but most metals are. I don't know about sodium, a metal, though, because it disintegrates in room air -- not practical to do a controlled experiment to prove about it being a good heat conductor or not. However, since those solids that are classified as a metal for the reason that each metal has free roaming electrons, which can be transport heat, and since solids also have phonons (lattice vibrations), sodium can conduct heat too (at least for the first mini-seconds of being exposed to air) -- just don't know whether sodium is a good heat conductor if it stands alone. BTW, mercury is a good heat conductor too. ===========================
Since most of the time we are concerned with heat being transferred via conduction, the denser the material, the easier it is to conduct heat. Except for the rare anomaly (think ice vs liquid water) solids are denser than their corresponding liquid forms. All that is a gross simplification of course. Many liquids heat quite a bit better than solids and convection (which can occur in liquids but not solids) can greatly aid in the speed of "heating up", so the generalization that solids heat up faster than liquids is only a tendency rather than a rule.
the heat expand the solids atoms
Germanium is a metal that does conduct heat, but does not conduct heat as well as other metals. This makes it a semiconductor.
Non-metals tend to not conduct heat
yes
Solids do conduct heat better than gases, although not necessarily better than liquids. Some solids are actually composite materials, because they can have a porous structure which contains gas within the solid, and this results in solids that do not conduct heat very well. But it is the gas component which has this insulating property.
Because they conduct heat less efficiently than do liquids or solids.
All objects conduct heat to some degree, even though some conduct it better than others. Objects are made out of matter, and that is the only requirement. If you want to know what an object would need to be made out of in order to conduct heat efficiently, that would be another question. Generally speaking, solids and liquids conduct heat better than gases so. Solids that contain trapped gas within them do not conduct heat as well as solids that don't.
Which group on the periodic table contains chemical elements that are brittle as solids and cannot conduct electricity
Materials that can conduct heat are called good conductors of heat and electricity. Most of the time, these materials are metals. Nonmetals are not good conductors of heat.
metals. they exist in the centre and on the left hand side of the table
Rubber is a excellent insulator of heat. The amount of hydrogen it is giving to keep track of heat. though if you are doing a science fair project, the amount of heat is excelled by the power of rubber
We normally associate metals with solids (at room temperature) -- mercury being one exception. All materials, solids or fluids, can conduct heat. However, not all solids are good conductors, but most metals are. I don't know about sodium, a metal, though, because it disintegrates in room air -- not practical to do a controlled experiment to prove about it being a good heat conductor or not. However, since those solids that are classified as a metal for the reason that each metal has free roaming electrons, which can be transport heat, and since solids also have phonons (lattice vibrations), sodium can conduct heat too (at least for the first mini-seconds of being exposed to air) -- just don't know whether sodium is a good heat conductor if it stands alone. BTW, mercury is a good heat conductor too. ===========================
salts
can a teapot conduct heat
Since most of the time we are concerned with heat being transferred via conduction, the denser the material, the easier it is to conduct heat. Except for the rare anomaly (think ice vs liquid water) solids are denser than their corresponding liquid forms. All that is a gross simplification of course. Many liquids heat quite a bit better than solids and convection (which can occur in liquids but not solids) can greatly aid in the speed of "heating up", so the generalization that solids heat up faster than liquids is only a tendency rather than a rule.