SCIENCE06L17： Classifications of Matter

Science 6. Classifications of Matter. Objectives. At the end of the lesson, you should be able to Familiarize oneself with the names of elements. Recognize the different compounds found in nature and their importance. Categorize mixtures according to their properties. Identify different types of solutions. Elements are substances that are made up of the same kind of atoms. They cannot be broken down into simpler chemical components. Hydrogen is an example, which is the lightest among all known elements Because it contains one electron and one proton. It is an element because it is made up of hydrogen atoms only. Other examples of elements are nitrogen, oxygen, gold, and calcium. What is an atom? Atom is the smallest unit into which matter can be divided Without the release of electrically charged particles. It is made up of protons and neutrons in their nucleus or the center of the atom. Protons are particles in an atom that are positively charged. Neutrons are particles that do not have charges. Electrons are negatively charged particles surrounding the protons and neutrons. Each element has been given a name and a symbol. Baron John's Jacob Berzelius, a Swedish chemist, Started to use chemical symbols when referring to an element. He used the initial letter of its Latin or common name in its capitalized form as follows. O is for Oxygen. H is for Hydrogen. C is for Carbon. However, if the element's name has the same initial as another element, Then two letters from the element's name are used. For example, Ni is for Nickel. Al is for Aluminum. Ca is for Calcium. Here are some elements that have symbols taken from their Latin names. Periodic table is a table of all the known elements arranged in order of increasing atomic mass. Artificial elements do not occur naturally on Earth, Which means they have been created by human through machines such as nuclear reactor or particle accelerator And even events like atomic bomb explosion. Elements are usually mixed with other substances when found in nature. The result of this combination is called a compound. A compound is a new substance formed when two or more elements are combined. The new substance formed has different characteristics and properties from the original elements. For example, Hydrogen and Oxygen are both gases. They are combined to form water. Water has two atoms of Hydrogen and one atom of Oxygen. The formula for a molecule of water is H2O. The number 2 written after letter H is small. It tells how many atoms of Hydrogen are present in one molecule of water. No number appears after letter O, which means there is only one atom of Oxygen present. Another example is the compound Sodium Chloride or also known as table salt. It is produced when Sodium reacts with Chlorine gas. When these two elements react to form a compound, Sodium and Chlorine lose their identity and an edible salt is formed. A mixture is a combination of two or more substances. There is an infinite number of mixtures. Anything that you combine is a mixture. Mixtures can be homogeneous or heterogeneous. A homogeneous mixture is made up of components that are equally distributed and blended together. Thus, the components are not recognizable. An example is vinegar, which is made of water and acetic acid. Other examples are soy sauce and orange juice. Heterogeneous mixture is a combination of substances that are not of uniform size and can be separated into its parts. Substances in this mixture retain their original properties. Examples are vegetable salads, a bowl of cereal with milk, a slice of pizza, and mixed nuts. Mixtures can also be classified into solution, suspension, and colloid. A solution is a homogeneous mixture in which one of the substances dissolves in the other. The most common solution are liquid solutions. A solute is the substance to be dissolved, while the solvent is the one dissolving the solute. A concentrated solution consists of large amount of solute in the solution. A diluted solution has a large amount of solvent. A saturated solution contains the maximum amount of solute that the solvent in the solution can dissolve. But not all solutions are liquids. There are mixtures of solids and gases too. A gaseous solution is made by mixing two or more gases. Air is a solution of nitrogen, oxygen, and several other gases. A solid solution can be a mixture of two or more metals, which is called alloy. Examples are steel, gold, and silver jewelry. A suspension is a heterogeneous mixture, which has particles that settle at the bottom and do not completely dissolve. For example, a liquid antibiotic needs to be shaken well before taking it. This is because the antibiotic has big particles that do not dissolve but rather settle at the bottom. Another example of a suspension is when you mix sand with water. The sand will sink to the bottom. A colloid is a special kind of mixture that contains very tiny particles that cannot be seen by the naked eye. The tiny particles do not settle down. It consists of slightly bigger particles than those in other solutions. In liquid colloids, the particles keep moving about in a dispersed phase within the liquid medium. This dispersed phase scatters the light focused on the mixture. An example is milk. Tyndall effect refers to how particles of colloidal matter scatter light by making a beam of light whenever the particles are lighted. Practice exercise. What is the basic unit of matter? Answer. Atom. What do you call substances that are made up of the same kind of atoms that cannot be broken down into simpler chemical components? Answer. Elements. What is the result when two or more elements are combined? Answer. Compounds. What is the type of mixture in which its components are not recognizable? Answer. Homogenous mixture. What do you call the heterogeneous mixture with solute that does not dissolve and only settle at the bottom? Answer. Suspension.