NOTE: This presentation was not made for public use. Please do not use this presentation without my permission and the permission of each of the authors of the photographs, quotes, and other materials that they contain. Thank you, Vicki Hughes Labs and Activities that go with this presentation: Let’s Get Chemical

Chemistry is the study of elements. Elements are made of atoms. Elements = natural substances that cannot be broken down into simpler substances. Which one of these items is an element? X ATOMS AND ELEMENTS

All elements are composed of atoms. Elements are identified by their protons. 1 proton = hydrogen 2 protons = helium 6 protons = carbon 8 protons = oxygen All elements are composed of atoms. Elements are identified by their protons. 1 proton = hydrogen 2 protons = helium 6 protons = carbon 8 protons = oxygen All matter is made up of individual particles called atoms, which cannot be divided. John Dalton You Can’t Touch Anything 5:29

Matter is anything that has mass and occupies space. All matter is made of atoms. Atoms are the smallest form of elements. About 100 elements Hydrogen is an element that accounts for about 90% of total mass of the universe. Hydrogen makes up about 1% of Earth’s crust and most of that is in water.

All of an atom’s positive charge is concentrated in the nucleus. Ernest Rutherford

Structure of an Atom Proton = positive charge Neutron = no charge The number of protons and neutrons varies with each element, however they are usually equal to each other. Electron = negative charge Protons and neutrons are grouped together in the nucleus. (Atomic Mass) e- Electrons are located outside the nucleus and are in motion. e-

Atomic Mass = protons + neutrons # of Neutrons = Mass Number – Atomic Number Atomic Mass? = 12 # of electrons? 6 protons balanced by 6 electrons Atomic Mass? = 12 # of electrons? 6 protons balanced by 6 electrons Atomic Number = Number of protons

ISOTOPES: variations of an element Have a different number of neutrons but same number of Protons Designated by the name of the element and its atomic mass number. Normal carbon nucleus (ACT L6 and EOG L1)

Dimitri Mendeleev I have created a periodic table where the elements are arranged according to their number of protons. This puts elements with similar properties in the same column. Yes, clearly I am a genius! Just watch this… SciShow Mendeleev’s Perioidc Table wu0LixSBpk&list=UUZYTClx2T1of7BRZ86-8fow

The periodic table organizes the atoms of the elements by properties and atomic number. Atomic Numbers PERIODIC TABLE OF THE ELEMENTS

Group – elements in a column with similar chemical and physical properties. Period – horizontal rows. Shows progression of the chemical properties of the elements. GROUP PERIOD

GROUP PERIOD Elements on the left of a period have a lower atomic mass than elements on the right of a period. Elements at the bottom of a group have more protons than elements at the top of the group.

Which elements are most reactive? METALS METALOIDS NONMETALS

Each element has a symbol that is used only for that element. C Symbol Symbols you should know: C = carbon O = oxygen N = nitrogen H = hydrogen Mg = magnesium Na = sodium Cl = chlorine K = potassium Symbols you should know: C = carbon O = oxygen N = nitrogen H = hydrogen Mg = magnesium Na = sodium Cl = chlorine K = potassium

Each element has a box that provide information about that element. C Atomic # Atomic Mass Symbol

How do you calculate the number of neutrons? Neutrons = Atomic Mass – Atomic Number C Atomic # Atomic Mass

ELECTRON CONFIGURATION Valence Electrons = electrons in outermost shell.

Lewis Structures Show the valence electrons in an atom – just the outmost level N Drawing Lewis Dot Diagrams

Atoms are NEUTRAL if they have all of their electrons. Carbon is neutral if it has 6 electrons. C Atomic # Atomic Mass

Noble gases -- Group 8 have full electron shells least likely to combine with other elements

NaCl Who will lose and who will gain an electron? + Atoms gain electrons (negatives) and become more negative. Atoms with 2-3 valence electrons will LOSE electrons and become more positive. MOLECULES, COMPOUNDS, and CRYSTALS (EOG L3)

Atoms have no overall electrical charge. Ions have charges because they have gained or lost an e-. x Lost 1 e- Became positive _ + Gained 1 e- Became negative

Molecular hydrogen (H 2 ), molecular oxygen (O 2 ) and molecular nitrogen (N 2 ) are not compounds because each is composed of only one kind of element. Molecule = two or more atoms join together chemically. Compound = molecule with at least two different elements. H-H O=O : : :: : : N=N : : = This is a molecule, but… …it is NOT a compound!

Water (H 2 O), carbon dioxide (CO 2 ) and methane (CH 4 ) are compounds because each is made from more than one element. O H H O=C=O : : : : This is a molecule, AND… …it is also a compound!

Element, Molecule, Compound, or Isotope? 1. water 2. carbon dioxide 3. oxygen gas (O2) 4. helium 5. carbon with an atomic mass of carbon with an atomic number of 6 7. carbon with 8 neutrons 8. carbon with an atomic mass of 14

A mixture is matter made up of two or more substances that combine physically only. Blood Trail Mix Soil In Heterogenous Mixtures substances are not distributed evenly throughout the mixture. Cup of Lucky Charms. MIXTURES

Mixin ’ It Up! In Homogenous Mixtures substances are distributed evenly throughout the mixture. Mustard, Ketchup, small cup, stirrer

Mixin ’ It Up! Solutions are homogenous mixtures in which one substance dissolves completely into the other. Solvent is the substance that does the dissolving. Solute is the substance that gets dissolved. Drink mix, water, cup, stirrer

Separation Anxiety! How do you separate mixtures? Sifting = separation by particle size.

Separation Anxiety! How do you separate mixtures? Filtration = separating a solid from a liquid in a heterogenous mixture. Filtration = separating a solid from a liquid in a heterogenous mixture.

Separation Anxiety! How do you separate mixtures? Evaporation = separating a solid from a liquid in a solution.

Boiling Point = point at which matter changes from a liquid to a gas. Melting Point = point at which matter changes from a solid to a liquid. Freezing Point = point at which matter changes from a liquid to a solid. Physical Properties PHYSICAL AND CHEMICAL CHANGES

Properties of Matter Physical Properties Conductivity = ease with which electrons move through the material. Magnetism = ability to be attracted or repelled by another materials due to a magnetic field. Malleability = ability to be hammered or rolled into sheets. Ductility = ability to be pulled and stretched into wire. Solubility = measure of the ability to dissolve in another substance (Solute is what is being dissolved and the Solvent is what is doing the dissolving)

Density is a Physical Property Density is the amount of mass contained in a unit volume. PHET Density

Properties of Matter Chemical Properties Reactivity = ability of a material to combine with or change into another substance.

Ways to Change Matter Density decreases as temperature increases! Increasing Heat

Ways to Change Matter Motion of particles increases as temperature increases! Increasing Heat

What is a chemical reaction? A chemical reaction is the change of a substance into a new one that has a different chemical identity. How can I tell if a chemical change is occurring? emission of light a change in temperature formation of a precipitate (a solid substance that settles to the bottom) evolution of a gas a color change =gs0j1EZJ1Uc Glowsticks

Any Questions? EOG L4 & L5