Compounds, Mixtures and Stages of Matter


Chemistry


Compound, Mixtures and Stages of Matter

There are several ways elements can be combined to make new materials. The two major categories are chemical compounds and chemical mixtures. Chemical mixtures can easily be separated because the elements do not change. This can be demonstrated to the child by putting rocks, grass and dirt into a bucket. Allow the kids to separate the "elements" that are in the bucket.

Chemical compounds are made when the elements share electrons or when the elements involved have opposite , positive and negative charges, and are therefore attracted to each other. Salt is a good example of this. Chemical compounds are not as easy to separate as chemical mixtures. Allow the kids to try to separate the ingredients in a piece of bread. Ask them if they can take out the flour, egg or salt, from the slice of bread.

There are two kinds of chemical compounds.
Covalent chemical compounds are made when the elements/atoms share electrons, this is how water molecules stick together. When atoms share electrons, the atoms are stuck together because one electrons is zooming around both atoms and that holds them together.

Another kind of chemical compound is an Ionic compound. This occurs when the elements involved have opposite positive and negative charges and are therefore attracted to each other (like salt). You know the old saying , opposites attract. An atom that has more electrons than protons has a negative charge. An atom that has more protons than electron has a positive charge. Atoms with opposite charges will stick together, forming a molecule.

Both kinds of compounds are very hard to separate. A mixture can easily be separated because there is nothing holding the atoms together, but a compound is held together by one of the two above methods.

Atoms do not always have an exact number of electrons. Atoms of all kinds are constantly trading electrons with each other. An example of this is static electricity. When you get a shock, you are collecting electrons from something else, like the T.V. If you rub your feet on the carpet you are losing your electrons and then when you touch something, you get them back with a ZAP!

Stages of matter
Elements can be in 3 stages or states. The three stages of matter are:
Solid
Liquid
Gas
Okay...there is actually a fourth stage of matter, plasma. But plasma in normally only found on the sun, and in rare cases on earth.

Water can be a solid, a liquid and a gas. Boil some water to show kids the "gas". Show them ice and water and explain the stages.

The copyright of the article Compounds, Mixtures and Stages of Matter in Homeschool Science is owned by Lisa Hawkins. Permission to republish Compounds, Mixtures and Stages of Matter in print or online must be granted by the author in writing.

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