Warm-up #1 Use a sheet of notebook paper to do your daily warm-up. You will turn them in every few weeks. 175 kg = _________ g Write .00074953 in scientific notation What things should be included in a graph.

Chapter 2 Notes Chemistry Review

Matter Is anything that has mass and takes up space It is NOT- ENERGY

There are 3 states of matter Solid- molecules are very closely packed; definite shape and volume

There are 3 states of matter Liquid-molecules have more energy and are further apart, indefinite shape but has a definite volume

There are 3 states of matter Gas- most energy among molecules; take the shape of container and fills space available; indefinite shape and volume

Physical Changes Changes in substances that involve changing states or simply cutting the substance in half are called physical changes

Chemical Changes Changes that break chemical bonds and change the substance into another substance are known as chemical changes.

Is this a physical or chemical change? Baking a cake Cutting down a tree Cooking chicken Melting ice Burning wood Boiling water Chemical Physical Chemical Physical Chemical Physical

Atom Basic unit of matter: atom Protons with a positive charge Electrons with a negative charge Neutrons with a neutral charge/ no charge

Nucleus Protons and neutrons are the two particles located in the nucleus, and they have a mass of 1 amu (atomic mass unit)

Electrons Electrons are located around the nucleus in electron clouds- (NOT actually in rings!), and they have a negligible mass because they are hundreds of times smaller than protons and neutrons.

Elements Elements are pure substances made up of one kind of atom. All atoms of that element look just the same, with the same number of protons, neutrons (average), and electrons. The number of protons indicates the type of atom.

Elements Letters = a symbol for the element- representation Atomic Number = Number of protons Atomic Mass (weight) = mass of nucleus (# protons + # neutrons)

How many electrons are there? The number of protons are the SAME as the number of electrons, which gives it a neutral charge So how many electrons are in Cobalt? 27

Atom models The protons and neutrons are drawn in the nucleus and the electrons around the nucleus in energy levels (rings) You will learn how to draw atoms in Chemistry Click photo to play video

Warm-up #2 In what state of matter do the molecules have the most energy? What element has 24 protons? What 2 parts make up the nucleus of an atom? Are fireworks a physical or chemical change?

Sodium Atomic number Nucleus (protons + neutrons) Symbol Element electrons Atomic mass

How many _____ are in this picture? Protons? Neutrons? Electrons? What is the atomic number? So what element is it? 6 6 6 6 Carbon

Ions Ions are charged atoms with extra or fewer electrons than they have as an uncharged atom. They gain or lose electrons in order to become stable. A full electron level is considered stable.

Ions Would our Sodium atom gain or lose electrons to become stable?

Isotopes Isotopes are uncharged atoms with a different atomic mass than the common element. Count the number of neutrons in each isotope of carbon above

Isotopes Some isotopes are radioactive and break down at a constant rate over time. We can use these to help date rocks and fossils, use them to treat cancers, and use them as biological markers within an organism

Bonding 3 Types: Ionic Bonds Covalent Bonds Hydrogen Bonds

Ionic Bonds electrons are transferred between a metal and a non-metal strong force examples: NaCl , CaS, MgCl2 Click photo to play video

Covalent Bond actually SHARE electrons between non-metals strong force example: CO2, NO2 Click photo to play video

Hydrogen Bonds form between water molecules very weak force We will discuss this in detail in 2.2 notes

Compounds A molecule is two or more atoms bonded together Examples: O2 (oxygen gas), N2 (Nitrogen gas), Cl2 (Chlorine gas), O3 (ozone) The physical and chemical properties of a molecule and compound are very different than the elements alone

Compounds A compound is two or more atoms of different kinds bonded together in definite proportions.  All compounds are molecules, but not all molecules are compounds  Examples: H20, CO2, C6H12O6 (sugar)

Subscripts written below the level of line signify # atoms in molecule if 1, then it is understood Ex: 1 Mg atom + 2 Cl atoms  MgCl2 Polyatomic ions- group together as one written in parenthesis, you must multiply through, just like in math (order of operations!)

Subscripts Ex: Al(NO3)3 There is __ Al, __ N and __ O Ex: (CH3)3CH There ___ C and ___ H 1 3 9 4 10

Coefficients written to the left of the molecule signify # of molecules Ex: 5NaCl 1 Na and 1 Cl in each molecule 5 molecules of NaCl  10 total atoms. Ex: 3 NO2 3 6 ___ N and ___ O