Table of ContentsM-6 Mission 6 Notes Part I Chapter: Matter Section 1: Atoms Section 2: Combinations of Atoms Section 3: Properties of Matter
Atoms1 The Building Blocks of Matter• Matter is anything that has mass and takes up space.• Heat and light are not matter, because they have no mass and do not take up space.
Atoms1 Atoms• The forms or properties of one type of matter differ from those of another type because matter is made up of tiny particles called atoms.
Atoms1 Atoms• The structures of different types of atoms and how they join together determine all the properties of matter that you can observe.• Like atoms, the same few blocks can combine in many ways.
Atoms1 The Structure of Matter• The building blocks of matter are atoms.• The types of atoms in matter and how they attach to each other give matter its properties.
Atoms1 Elements• Most other objects that you see also are made of several different types of atoms.• Some substances are made of only one type of atom.• Elements are substances that are made of only one type of atom and cannot be broken down into simpler substances by normal chemical or physical means.
Atoms1 Elements• Minerals usually are combinations of atoms that occur in nature as solid crystals and are usually found as mixtures in ores.• Some minerals, however, are made up of only one element.• These minerals, which include copper and silver, are called native elements.
Atoms1 Modeling the Atom• When something is too large or too small to observe directly, models can be used.• A model is a small version of a larger object.
Atoms1 The History of the Atomic Model• More than 2,300 years ago, the Greek philosopher Democritus (di MAH kruh tuss) proposed that matter is composed of small particles called atoms.• More than 2,000 years later, John Dalton expanded on these ideas. He theorized that all atoms of an element contain the same type of atom.
Atoms1 Protons and Neutrons• Three basic particles made up an atom— protons, neutrons (NOO trahnz), and electrons.• Protons are particles that have a positive electric charge.• Neutrons have no electric charge.
Atoms1 Protons and Neutrons• Both particles are located in the nucleus—the center of an atom.• With no negative charge to balance the positive charge of the protons, the charge of the nucleus is positive.
Atoms1 Electrons• Particles with a negative charge are called electrons, and they exist outside of the nucleus.• In 1913, Niels Bohr, a Danish scientist, proposed that an atom’s electrons travel in orbitlike paths around the nucleus.
Atoms1 The Current Atomic Model• Over the next several decades, research showed that electrons can be grouped into energy levels, each holding only a specific number of electrons.• Also, electrons do not travel in orbitlike paths. Instead, scientists use a model that resembles a cloud surrounding the nucleus. Click image to view movie.
Atoms1 Counting Atomic Particles• The number of protons in an atom depends on the element.• All atoms of the same element have the same number of protons.• For example, all iron atoms contain 26 protons, and all atoms with 26 protons are iron atoms.
Atoms1 Counting Atomic Particles• The number of protons in an atom is equal to the atomic number of the element.• This number can be found above the element symbol on the periodic table.
Atoms1 How many electrons?• In a neutral atom, the number of protons is equal to the number of electrons.• This makes the overall charge of the atom zero.• Therefore, for a neutral atom:Atomic number = number of protons = number of electrons
Atoms1 How many electrons?• Atoms of an element can lose or gain electrons and still be the same element.• Atoms with fewer electrons than protons have a positive charge, and atoms with more electrons than protons have a negative charge.
Atoms1 How many neutrons?• Unlike protons, atoms of the same element can have different numbers of neutrons.• The number of neutrons in an atom isn’t found on the periodic table. Instead, you need to be given the atom’s mass number.
Atoms1 How many neutrons?• The mass number of an atom is equal to the number of protons plus the number of neutrons.• The number of neutrons is determined by subtracting the atomic number from the mass number.
Atoms1 How many neutrons?• For example, if the mass number of an atom is 14 and its atomic number is six; it has eight neutrons.
Atoms1 How many neutrons?• Atoms of the same element that have different numbers of neutrons are called isotopes.
Section Check1 Question 1__________ is anything that has mass andtakes up space.A. calorieB. HeatC. LightD. Matter
Section Check1 AnswerThe answer is D. Heat and light are not matterbecause they have no mass and do not take upspace.
Section Check1 Question 2Particles in an atomic nucleus that have noelectric charge are __________.A. electronsB. neutronsC. protonsD. quarks
Section Check1 AnswerThe answer is B.Electrons have anegative electriccharge and protonshave a positivecharge.
Section Check1 Question 3The mass number of an atom is equal to__________.A. the number of electronsB. the number of electrons and protonsC. the number of protonsD. the number of protons and neutrons
Section Check1 AnswerThe answer is D. The number of protons andneutrons in an atom is the mass number of theelement.
Section Summary• Section 1 Summary ATOMS• Matter is anything that has mass and takes up space• The nucleus of an atom contains protons with a positive charge and neutrons with no charge. Electrons, which have a negative charge, surround the nucleus.• Isotopes are atoms of the same element that have different numbers of neutrons.• Diagram of an Oxygen molecule
Combinations of Atoms2 Interactions of Atoms• There are about 90 naturally occurring elements on Earth.• A few elements produce many different things because elements can combine in countless ways.• Each combination of atoms is unique.
Combinations of Atoms2 Compounds• When the atoms of more than one element combine, they form a compound.• A compound contains atoms of more than one type of element that are chemically bonded together.• Water is a compound in which two hydrogen atoms are bonded to each oxygen atom.
Combinations of Atoms2 Compounds• Compounds are represented by chemical formulas that show the ratios and types of atoms in the compound.• For example, the chemical formula for water is H2O.• The properties of compounds often are very different from the properties of the elements that combine to form then.
Combinations of Atoms2 Chemical Properties• A property that describes a change that occurs when one substance reacts with another is called a chemical property.• The chemical properties of a substance depend on what elements are in that substance and how they are arranged.
Combinations of Atoms2 Bonding• The forces that hold the atoms together in compounds are called chemical bonds.• These bonds form when atoms share or exchange electrons.
Combinations of Atoms2 Separating Mixtures and Compounds• Separating the components of a mixture is a relatively easy task compared to separating those of a compound.• The substances in a compound must be separated by chemical means.• This means that an existing compound can be changed to one or more new substances by chemically breaking down the original compound.
Combinations of Atoms2 Exploring Matter• Seashells and coral reefs contain calcium carbonate, which has the formula CaCO3.• Properties of CaCO3 differ greatly from those of its elements, calcium, carbon, and oxygen.
Section Check2 Question 1Chemical bonds form when atoms share orexchange __________.A. electronsB. neutronsC. nucleiD. protons
Section Check2 AnswerThe answer is A. Only the electrons having thehighest energy in the electron cloud can formbonds.
Section Check2 Question 2What is the difference between a compoundand a molecule? AnswerCompound refers to any substance in whichatoms of more than one type of element arechemically bonded together. A molecule is theindividual unit or group of atoms connected bycovalent bonds.
Section Check2 Question 3How do compounds differ from mixtures? AnswerIn compounds, atoms of more than one type ofelement are chemically bonded together.Mixtures are composed of two or moresubstances that are not chemically combined.
Section Summary• Section 2 Summary Combination of Atoms• Atoms join to form compounds and molecules. A compound is a substance made of two or more elements. The chemical and physical properties of a compound differ from those of the elements of which it is composed.• A mixture is a substance in which the components are not chemically combined.
Properties of Matter3 States of Matter• On Earth, matter occurs in four physical states.• These four states are solid, liquid, gas, and plasma. Click image to view movie.
Properties of Matter3 Solids• The reason some matter is solid is that its particles are in fixed positions relative to each other.• The individual particles vibrate, but they don’t switch positions with each other.• Solids have a definite shape and take up a definite volume.
Properties of Matter3 Liquids• Particles in a liquid are attracted to each other, but are not in fixed positions as they are in the solid.• The particles in a liquid can change positions to fit the shape of the container they are held in.
Properties of Matter3 Gases• The particles that make up gases have enough energy to overcome any attractions between them.• This allows then to move freely and independently.• Unlike liquids and solids, gases spread out and fill the container in which they are placed.
Section Check3 Question 1___________ is a measure of the mass of anobject divided by its volume.A. AreaB. DensityC. ForceD. Viscosity
Section Check3 AnswerThe answer is B. This measurement is usuallygiven in grams per cubic centimeter.
Section Check3 Question 2Which of the following is the most commonstate of matter in the universe?A. gasB. liquidC. plasmaD. solid
Section Check3 AnswerThe answer is C. Stars like the Sun arecomposed of plasma.
Section Check3 Question 3Which state of matter spreads out and fills itscontainers?A. gasB. liquidC. plasmaD. solid
Section Check3 AnswerThe answer is A. Liquids will take the shape ofcontainers, but will not necessarily fill them.
Section Summary• Section 3 Summary Properties of Matter• Physical properties can be observed and measured without causing a chemical change in a substance.• Chemical properties can be observed only when one substance reacts with another substance.
Section Summary• Atoms in a solid are fixed in place• Atoms in a liquid are close together but still can move• Atoms in a gas move quickly and freely• The only substance found in all 3 phases on Earth is water• Density = Mass/Volume• If a substance is more dense than water it will FLOAT!• If a substance is less dense than water it will SINK!