Entrance Question Complete “I see, I think, I wonder” for the image below. I see _______________________________________. I think ______________________________________. I wonder ____________________________________. A B C

Elements and Compounds

Elements There are currently 118 elements that have been identified, though only 98 of them are naturally occurring.

Elements in the Universe In our universe, hydrogen makes up 75% of all matter! Helium makes up about 20% of all matter. Oxygen is the 3rd most abundant element.

Elements in the Earth In the Earth’s crust, oxygen is the most abundant element (46.6%). Silicon is the second most abundant element (27.7%). Aluminum (8.1%), iron (5.0%), calcium (3.6%), sodium (2.8%), potassium (2.6%). and magnesium (2.1%) complete the list of elements that account for approximately 99% of the total mass of the earth's crust.

Elements Elements are pure substances. Made of only one kind of material, has definite properties, and is the same all throughout. Elements are the simplest pure substance. They cannot be broken down into simpler substances without losing their identity.

Elements and Atoms The smallest particle of an element that has the properties of that element is called an atom. Atoms: the building blocks of matter. Atoms of the same element are alike; atoms of different elements are different.

Elements and Atoms In the center of every atom is a nucleus containing: Protons (positive charge) Neutrons (no charge) In constant motion on the outside of the nucleus are negatively charged electrons. https://www.youtube.com/watch?v=jZO6W-DEVLk

Chemical Symbols This is a shorthand way of representing the elements. Symbols are usually one or two letters. Usually taken from the name of the element: Carbon-C, Calcium-Ca, Hydrogen-H, Iodine-I, Oxygen-O, Chlorine-Cl

Chemical Symbols Atomic number: 2 Atomic mass: 4.00 amu (number of protons) Atomic mass: 4.00 amu (number of protons + neutrons) Fun Fact: 602,213,665,200,000,000,000,000 amu in 1 gram

Chemical Symbols Some symbols come from their Latin name: Gold - Au -- aurum Silver - Ag -- argentum Iron - Fe -- Ferrum Mercury - Hg -- hydrogyrum

Compounds Pure substances made up of more than one element. 2 or more elements chemically combined. Ex: H2O, NaCl, C6H12O6, CO2 Unlike elements, compounds can be broken down into simpler substances. You cannot separate compounds by physical means. This only happens through a chemical reaction. (water) (salt) (glucose) (carbon dioxide)

Compounds Demo Mystery Substance 1- NaHCO3 (solid) Mystery Substance 2 - CH3COOH (liquid) NaHCO3 + CH3COOH → CO2 + H2O + Na+ + CH3COO-

Compounds The properties of the elements that make up a compound are often quite different from the properties of the compound itself. Sodium - Na -- highly reactive metal Chlorine - Cl -- poisonous gas Combined: Sodium Chloride - NaCl --table salt

Molecules Compounds are made of molecules. A molecule is 2 or more atoms chemically bonded. Water-2 atoms of hydrogen and one atom of oxygen-together they form one molecule of H2O. A molecule is the smallest particle of a compound that has all the properties of that compound. Just as all atoms of a certain element are alike, all molecules of a certain compound are alike.

Chemical Formulas A shorthand way of representing compounds. Ex: NH3 - ammonia, C3H7OH - rubbing alcohol Sometimes, the formula represents a molecule of one kind of element. These are called diatomic molecules. This is how that element is naturally found. O2-Oxygen H2-Hydrogen Cl2-Chlorine

Chemical Formulas Subscripts are small numbers used in chemical formulas. They are placed to the lower RIGHT of the chemical symbols. Subscripts represent the number of atoms of an element in a compound. Examples: CO2 = 1 atom of carbon and 2 atoms of oxygen. H2SO4 = 2 atoms of hydrogen, 1 atom of sulfur and 4 atoms of oxygen

Chemical Formulas Practice a. KNO3 b. K2CO3 c. NH4NO2 d. BaSO4 e. HgNO2

Chemical Formulas Practice f. Hg2Cr2O7 g. ZnCrO4 h. Fe(OH)2 i. Al(NO3)2 j. Fe2(Cr2O7)3

Entrance Questions (Review) Directions: Label each as an element or compound: 1.) _______________ Copper (Cu) 2.) _______________ Ammonia (NH3) 3.) _______________ Mercury (Hg) 4.) _______________ Starch (C6H10O5) 5.) How many atoms of hydrogen are in starch? 6.) How many atoms of nitrogen are in ammonia?

Atoms Review Element: Carbon http://phet.colorado.edu/en/simulation/build-an-atom Element: Carbon

Elements Pure substance; one type of atom Hydrogen (H) Helium (He) Gold (Au) Copper (Cu) Mercury (Hg) What are a few more? Diatomic molecules: (H2, N2, O2, etc.) Element existing in the form of atoms Element existing in the form of diatomic molecules

Compounds Pure substance; made of more than one type of element NaCl (salt) CO2 (carbon dioxide) H2O (water) NaHCO3 (baking soda) Compound whose molecules consist of one atom of an element and two atoms of another element

Mixtures combination of two or more substances that have not been combined chemically can be separated into their original parts by physical means (Ex: distillation of liquids, separating magnetic and non-magnetic solids using a magnet, etc.) https://www.youtube.com/watch?v=sHGOcmSrfp0 have many of the properties of their original parts

Mixtures

Mixtures Mixture of element and element Mixture of molecule and molecule

Mixtures Mixture of an element and a molecule Mixture of a compound and a molecule

Review: Can you identify the following? You will be shown a series of photos. Tell if each photo represents an item composed of an element, compound, or mixture. Review: An element contains just one type of atom. A compound contains two or more different elements joined together chemically. A mixture contains two or more different substances that are only physically joined together, not chemically. A mixture can contain both elements and compounds.

Element, Compound, or Mixture? Rocks

Element, Compound, or Mixture? Rocks

Element, Compound, or Mixture? Copper

Element, Compound, or Mixture? Copper (Cu)

Element, Compound, or Mixture? Jelly Beans

Element, Compound, or Mixture? Jelly Beans

Element, Compound, or Mixture? Table Sugar

Element, Compound, or Mixture? Table Sugar (C12H22O11)

Element, Compound, or Mixture? Tea

Element, Compound, or Mixture? Tea

Element, Compound, or Mixture? Salt

Element, Compound, or Mixture? Salt (NaCl)

Element, Compound, or Mixture? Neon Gas

Element, Compound, or Mixture? Neon Gas (Ne)

Element, Compound, or Mixture? Salad

Element, Compound, or Mixture? Salad

Element, Compound, or Mixture? Pure Water

Element, Compound, or Mixture? Pure Water (H2O)

Element, Compound, or Mixture? Aluminum

Element, Compound, or Mixture? Aluminum (Al)

Element, Compound, or Mixture? Lemonade

Element, Compound, or Mixture? Lemonade

Element, Compound, or Mixture? Silver

Element, Compound, or Mixture? Silver (Ag)

Element, Compound, or Mixture? Sand

Element, Compound, or Mixture? Sand

Entrance Question A, B, C, and D are all examples of different substances. Label each example as an element, compound, or mixture. Explain your answers! A B C D

Period Table of Elements Review Elements: A pure substance containing only one kind of ____________. An element is always the same all the way through. An element _____________ be separated into simpler materials (except during nuclear reactions). Over 100 existing elements are listed and classified on the ____________________. atom cannot Period Table of Elements

Review Atoms: An atom is the smallest part of an element. Ex: One atom of Hydrogen At the center of an atom is a ________________, containing ______________ and ________________. Atoms have are neutral in charge because they have an equal amount of ______________ and _____________. An atom’s atomic number tells the number of __________ in the atom’s nucleus. An atom’s atomic mass does not include the atom’s _____________ because they are extremely small. nucleus protons neutrons protons (+) electrons (-) protons electrons

Review Compounds: A pure substance containing two or more kinds of _______________. The atoms are _________________ combined in some way. Often times (but not always) they come together to form groups of atoms called molecules. A compound is always the same throughout. Compounds ___________________ be separated by physical means. Separating a compound requires a chemical reaction. The properties of a compound are usually _____________ than the properties of the elements it contains. elements chemically cannot different

Review Mixtures: Two or more ________________ or _________________ NOT chemically combined. There is no chemical reaction between its substances. Mixtures _____ be separated into their components by physical means. The properties of a mixture are ____________ to the properties of its components. elements compounds can similar

Roundtable Consensus Group Practice Why Roundtable Consensus Groups? All students are involved; students must work together; groups have great discussions/debates. Rules: Students work on their own for each question. Once all students are finished with a question, the group discusses their answers. The group must agree on ONE final answer before moving on to the next question. If there is a disagreement in answers, be respectful while giving your reasoning. Students may NOT work ahead of their group!

Roundtable Consensus Group Practice

Entrance Question Draw a model of one atom of Lithium (Li). ***Round its mass to the nearest whole number (7). Hint: The atomic number tells us the number of ___________ in the nucleus. Hint: The atomic mass is the sum of protons and neutrons. http://phet.colorado.edu/en/simulation/build-an-atom

Elements, Compounds, & Mixtures Wkst

Element, Compound, & Mixture Practice

Element, Compound, & Mixture Practice Books on these tables