Rock Cycle - Chemistry (2)
Post Lab 

  • Counting the number of elements that are solids, liquids, and gases.
  • Exploring the states of matter of elements.
  • element
  • gas
  • liquid
  • periodic table
  • solid

Students discover the state of matter of individual elements.


When elements combine to make molecules they sometimes loose the state of matter they were in when they were an element. For instance, hydrogen and oxygen are gases, but when you combine them the normal condition would be liquid (water). Silicon is a solid, and oxygen is a gas; when you combine them they sometimes become quartz, which is a solid. Carbon is a solid and oxygen is a gas; when they combine they become a gas.

States of matter can change even within normal conditions on Earth. If water (hydrogen + oxygen) is frozen, it is ice; when heated, it is a gas. Water is actually one of the few molecules that can change from the three states of matter easily on Earth. Most other elements and compounds cannot do that.

  1. Pass out the Periodic Table placemats and the student worksheets. Ask them to count all the gaseous elements. Record this number on the worksheet. Next ask them to count all the liquids. Again, record this number on the worksheet. Finally, have them count all the solids.

    On the Periodic Table Placemat, the elements that are solids, liquids, and gases are differentiated by color. This refers to the state of matter that they are in on the Earth’s surface, under normal conditions. Note that plasma is not a form of matter that elements take. There are 11 gases, 4 liquids, and 94 solids on this periodic table.

  2. Tell students that not all elements can be found in a pure state, meaning that the element naturally occurs in combination with other elements rather than by itself. There are 18 elements that are synthetically made. These are created by scientists. We really do not know what their natural form would be since they are unstable in the natural environment of Earth's surface. These synthetic elements have the atomic numbers 61, 93-109. Have the students write the symbol of these elements on their worksheets. Say the name of each of the elements and have the students repeat the name.
  3. Explain to the students that when an element combines with other elements it forms a compound, which can be a different state of matter then its component elements. For example, hydrogen and oxygen are gases, but when combined they become water, a liquid.

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