State Changes of Elements


Changes of state happen when solids, liquids and gases change between each other due to energy being added or taken away.

Changes of state happen when solids, liquids and gases change between each other due to energy being added or taken away.

State changes can happen when heat energy is applied to solids liquids and gases they all behave differently. This is because the particles are weakly attracted to each other and this attraction needs energy to overcome it. When a substance is heated this causes the particles to vibrate and gain kinetic energy which can cause them to break away from each other changing state from solids to liquids to gas. Equally when an object is cooled down the heat energy is removed and the particles slow down coming together and the forces can attract to each other again.


Evaporation is the change of a liquid to a gas. this happens when a particle in a liquid has enough energy to break free from the attraction it has to other atoms in the liquid. It will move away from the liquid and will have a greater separation and distance between the particles.


Condensation is when a gas turns into a liquid. This happens when we cool down a gas we remove heat energy from it. By removing the heat energy the particles move slower and they can become attracted to each other and move closer to each other to form a liquid. The particles are not spaced out as much in a liquid than in a gas and are attracted to each other a little bit more.


When a solid turns into a liquid the particles in the solid which are fixed and regular begin to vibrate due to an increase in temperature as the particles vibrate so they overcome the attraction between the particles and can move more freely and with less order.


When a liquid is cooled and heat energy is removed from particles they will get closer and move slower and the attraction between them gets higher.

Why do elements have different states?

In the periodic table there are a different number of states. This is because they have different forces between the atoms called bonds. Some of the bonds are very strong for example in metals the atoms are held together with very strong bonds and these need a lot of energy to break them apart so most metals are strong and solids. Other elements like chlorine or fluorine have weaker bonds and these need less energy to break them apart so they are gases and do not need a lot of energy to cause them to break apart.

Terms in section
Kinetic energy

Kinetic energy is a measure of the amount of movement energy in atoms. Atoms that have a lot of kinetic energy tend to be gases and those that have little kinetic energy tend to be solids as they do not move a lot


Separation is a term to describe the distance between particles


Attractions are when atoms are close to each other and they are joined by a weak force this is known as an attraction


States of Matter


Physical Properties