Facts of Matter By Ms. Renfro

The two categories of matter Pure Substances Are chemically the same throughout Mixtures Substances that are not chemically combined

Pure substances Pure substances include: Atoms-the smallest part of all matter made of protons, neutrons, and electrons Elements- substances made up of only 1 type of atom MOLECULES ARE PURE SUBSTANCES THAT are formed from 2 or more Atoms Chemically combining Compounds- Elements that chemically combine to form a new substance http://studyjams.scholastic.com/stu dyjams/jams/science/matter/elements -and-compounds.htm

https://www.youtub e.com/watch?v=FofP jj7v414 Elements Pure substances made from only one type of atom Example: carbon only has carbon atoms, nitrogen only has nitrogen atoms Cannot be broken down into simpler substances…they are pure! Can be chemically combined to form compounds https://www.youtub e.com/watch?v=FofP jj7v414

What is the difference between atoms and elements? Atoms are the smallest bits of ordinary matter. Atoms are made from tiny particles called protons (positive), neutrons (no charge) and electrons (negative). The protons and neutrons cluster together in the central part of the atom, called the nucleus the electrons 'orbit' the nucleus. A particular atom will have the same number of protons and electrons and most atoms have at least as many neutrons as protons. An element is a substance that is made entirely from one type of atom. For example, the element hydrogen is made from atoms containing just one proton and one electron. Or the element gold, is made from atoms containing 79 protons and 79 electrons.

What is the difference between a compound and a molecule? A molecule is formed when two or more atoms join together chemically. A compound is a molecule that contains at least two different elements. All compounds are molecules but not all molecules are compounds. Molecular hydrogen (H2),  oxygen (O2) and nitrogen (N2) are not compounds because each is composed of a single element. Water (H2O), carbon dioxide (CO2) and methane (CH4) are compounds because each is made from more than one element. The smallest bit of each of these substances would be referred to as a molecule. For example, a single molecule of molecular hydrogen is made from two atoms of hydrogen while a single molecule of water is made from two atoms of hydrogen and one atom of oxygen.

Elements: pure substance There are over 120 elements and most (92) are found in nature. Fun Facts! Approximately 95% of your body is made of the elements Hydrogen __________ Carbon____________ Nitrogen______ Oxygen___________ Phosphorous_________ Calcium_____________

The Periodic table

Reading the periodic table Provides a wealth of information about elements Each element has a chemical symbol Atomic number- tells the number of protons in the nucleus Atomic mass-tells the mass of the protons and neutrons in the nucleus The number of protons= the number of electrons

How the periodic table is organized The basics The periodic table is arranged in order of increasing atomic number. The 2 main groups of elements on the periodic table are metals and non-metals. The metals are on the left side of the table moving to the non- metals on the right. The elements in the center are called transition metals. Metalloids are found along either side of the staircase.

How the periodic table is organized Groups/Families and Periods The vertical columns are called groups/Families The families have similar properties. They also have the same number of electrons on the outer shell, which are called valence electrons. Valence electrons are what determines an elements properties and reactivity. The most reactive elements are on the far left and the least reactive elements are on the far right of the periodic table. The horizontal rows are called periods. Each element in the same period have the same number of atomic orbitals, or electron shells (the path that electrons follow around the nucleus) http://www.chem4kids.com/files/elem_pertable.html

Metals, nonmetals Non-Metals Metals Shiny 'metallic' appearance Solids at room temperature (except mercury) Very reactive High melting points High densities Low electronegativities Usually, high deformation (can bend without breaking) Malleable Ductile Thermal conductors Electrical conductors High ionization energies High electronegativities Poor thermal conductors Poor electrical conductors Brittle solids Little or no metallic luster Gain electrons easily

Physical Properties of Metalloids Chemical Properties of Metalloids The Metalloids, or semi-metals, are elements with properties that share properties of metals and non-metals. Physical Properties of Metalloids State of Matter Solid Luster Metallic luster Elasticity Brittle Conductivity Semi-conductive. Average transmission of heat. Chemical Properties of Metalloids Oxidation Readily form glasses Alloys Form alloys with metals *Allotropic Several metallic and non-metallic allotropic forms Melting Some metalloids contract on melting Compounds Reacts with the halogens to form compounds https://youtu.be/9u6-V7Q3AS0

What is a physical property? A feature of matter that can be observed with your senses and measured without changing its identity.

Physical property examples States of matter If it’s a solid, liquid, gas, or plasma is a phys. Prop! Texture Color Density Luster Melting, boiling, freezing point Streak Odor Mass Volume Hardness

What is a Physical change? A change that causes a physical property to change but it doesn’t change the identity of the substance.

Examples of physical changes Matter changing states Freezing, melting, boiling Cutting, crushing, dissolving Losing or gaining mass ***What does the arrow represent in this picture? Solid liquid Gas plasma

What is a chemical property? The ability of matter to interact with something and change into a new substance with different properties. It requires a chemical reaction!

Examples of chemical properties Reactivity with oxygen When 2 or more substances combine to form a new substance. Example: water+oxygen +Iron Rust

Examples of chemical properties 2. Flammability- The ability of a substance to burn What cannot burn??  

3. How fast a substance can catch on fire or burst into flames! Combustibility 3. How fast a substance can catch on fire or burst into flames!

Chemical changes Happens when 1 or more substances are changed into new substances with new properties. Once there is a chemical change, it cannot change back!

Examples of chemical changes Souring milk- smells bad due to bacteria forming Bubbling when acid reacts with baking soda 3. rusting 4. Burning ** Chemical changes have chemical formulas because they are entirely new substances Example: H2O 1100321305