Matter: is anything that has mass and takes up space
Properties of Matter • Chemistry is the study of the properties of matter and how matter changes • Every form of matter has two kinds of properties physical properties and chemical properties.
Properties of Matter • Physical Property is a characteristic of a pure substance that can be observed without changing it into another substance • Examples: • Color • Texture • States of matter • Size • Temperature • Smell • Shape • Boiling point • Melting point • Density
Chemical Properties of Matter • Chemical property is a characteristic of a pure substance that describes its ability to change into a different substance • Examples: • Burning • rusting • Film processing
Elements • Elements are the simplest pure substance • Elements are often called the building blocks of matter because all matter is composed of one or more element or a combination of two or more elements.
Particles of Elements- Atoms • An atom is the basic particle from which all elements are made. • DIFFERENT ELEMENTS HAVE DIFFERENT PROPERTIES BECAUSE THEIR ATOMS ARE DIFFERENT!!
When Atoms Combine • The majority of element’s atoms combine with other atoms. • When atoms combine, they form a chemical bond—which is the force of attraction between two atoms.
Compounds • A compound is a pure substance made of two or more elements that are combined in a specific ratio. • Example: • Sodium chloride (table salt)
When elements are chemically combined, they form compounds having properties that are different from those of the uncombined elements.
Mixtures • A mixture is two or more substances-elements, compounds, or both—that are in the same place but not chemically combined. • Examples: • Gasoline • Soil • Air
Heterogeneous mixtures– you can see the different parts • Homogeneous mixtures – substances are mixed evenly
Changes In Matter Chapter One Section Three
Physical Change • A physical change is any change in the form or appearance of matter but does not change the substance.
A substance that undergoes a physical change is till the same substance after that change
Types of Physical Changes • Changes of state- moving from between solids, liquids, and gases. • Changes in Shape or form
Chemical Change • A change in matter that produces one or more new substance is a chemical change • A chemical change produces a new substance with properties that are different from those of the original substance.
Conservation of Mass • The fact that matter is not created nor destroyed in any chemical or physical change is called The law of conservation of mass
No mass is lost, because during a chemical change, atoms are not lost or gained, only rearranged
Matter and Energy • Energyis the ability to do work or cause change. • Every chemical or physical change in matter includes a change in energy.
Temperature and Thermal Energy • Temperature is the measure of the average energy of random motion of particles of motion. • Thermal energy is the total energy of all of the particles in an object. • Thermal energy always flows from warmer to cooler areas
Thermal Energy and Changes in Matter • Endothermic energy – a change in which energy is taken in or absorbed ( substance gets cold) • Exothermic Energy – when energy is given off (substance gets warm)
Introduction to Atoms Chapter three section one
Structure of an Atom • What is an element? • A pure substance that cannot be broken down into other substance by chemical of physical means • What is an atom? • The basic particle from which all elements are made up. • http://www.brainpop.com/science/matterandchemistry/atoms/
Particles of Atoms • An atom consists of a nucleus surrounded by one or more electrons. • Neutronfound in the nucleus of an atom (has no charge) • Protons found in the nucleus, have a positive electric charge (+) • Electronsmove rapidly around the nucleus and have a negative charge (e-)
A Cloud of Electrons • Electrons move within a sphere shaped region surrounding the nucleus. • Electrons with lower energy usually move in the space near the atom’s nucleus. • Electrons with higher energy move within the space farther from the nucleus.
A Cloud of Electrons • Most of the atom’s volume is the space in which electrons move. • The space is huge compared to the amount of space taken by the nucleus. • http://www.brainpop.com/science/matterandchemistry/atomicmodel/
Comparing Particle Masses • Electrons take up the majority of space in the atom but they account for very little of the mass. • It takes about 2,000 electrons to equal the mass of just one proton. • Together the proton and the neutrons make up nearly all the mass of an atom.
Comparing Particle Masses • Atoms are too small to be measured in everyday units of mass, such as grams or kilograms. • Scientists use atomic mass units (amu) to measure the mass of an atom.
Atomic Number • An element can be identified by the number of protons in the nucleus of its atoms • Every atom of an element has the same number of protons. • Each element has a unique atomic number – the number of protons in its nucleus.
Isotopes • Atoms with the same number of protons but different numbers of neutrons are called isotopes • An isotope is identified by its mass number which is the sum of the protons and neutrons in the nucleus of an atom
Ion • An atom where the total number of protons is not equal to the total number of electrons is an Ion • Results in a overall positive or negative charge
Modeling Atoms • One speck of dust may contain about one million billion atoms!!!!!!!!!! • Because atoms are so small, scientists create models to describe them. • Model-may be a diagram, a mental picture, a mathematical statement, or an object that helps explain ideas about the natural world.
Modeling Atoms • In chemistry, models of atoms are used to explain how matter behaves. • The modern atomic model explains why most elements react with other elements, while a few elements hardly reacts at all.
Organizing the Elements Chapter three section two
Pattern in the Elements • By 1869 there were 63 known elements. Each of these elements have different chemical and physical properties. • A Russian scientist, Dmitri Mendeleev, discovered a set of patterns that applied to all the elements in order to organize the elements. • http://www.brainpop.com/science/matterandchemistry/periodictableofelements/
Mendeleev’s Work • Elements have similar chemical and physical properties. • Example: • Fluorine and Chlorine –gases that irritate the skin • Silver and Copper – shinny metals that tarnish if exposed to air.
Mendeleev’s Work • Mendeleev started organizing elements by their color, density, melting point, atomic mass, and the number of chemical bonds the element can form. • The atomic massof an element is the average mass of all the isotopes of that element.
Mendeleev’s Work • He noticed that a pattern of properties appeared when he arranged the elements in order of increasing atomic mass