Bellringer – November 12, 2014 Look at the Periodic Table: What does the Au stand for? What atomic number is aluminum and what is it’s symbol? What 6 elements are WE mostly made up of? Look at the periodic table and take a guess!

Introduction to Chemistry Honors Biology Ms. Kim

Composition of Matter Matter - everything in universe is composed of matter (“stuff”) Matter is anything that occupies space or has mass Mass – quantity of matter an object has Weight – pull of gravity on an object

Chemistry of Life All matter is composed of tiny particles called atoms. There are 109 types of atoms - a substance made up of one kind of atom is called an element. An atom is the smallest part of an element that still has the properties of that element.

Atomic Structure Each atom is made up of smaller parts called protons, electrons and neutrons. Protons and neutrons are found in the central portion of the atom called the nucleus. Protons (+) in nucleus Neutrons (0) in nucleus Electrons (-) in a cloud outside!

There are SIX elements necessary for life – C – Carbon There are SIX elements necessary for life – C – Carbon H – Hydrogen N – Nitrogen O – Oxygen P – Phosphorous S- Sulfur CHNOPS The most important element is CARBON! Have students color their own, go through reading a periodic table, atomic #, weight, etc. and discuss patterns of elements in groups and periods Row = Period. Hydrogen and helium are in period one. Groups =Columns The periodic table tells you where the metallic, nonmetallic, and semimetallic metals are. To the right of the periodic table, starting to the left of boron (element #5, B) you should see a line that looks like a staircase. Elements far to the left of this line are metals, elements to the far right of this line are nonmetals, and elements right around the line on either side are semimetals, or metalloids. Alkali metals are group 1. They are highly reactive elements with low melting and boiling points. They are light, soft metals. They tend to form ions with a +1 charge. Alkaline earth metals are group 2. They are also reactive, but less so than the alkali metals. They are light, soft metals, but stronger and denser than the alkali metals. They tend to form ions with a charge of +2. Transition metals are in groups 3-12. They are less reactive than the alkali and alkaline earth metals, but vary greatly among themselves in reactivity. Generally, these elements form cations, but the amount of positive charge these elements have depends on what the metals are reacting with. Lanthanides are the metals in the 4f part of the periodic table. They are generally reactive, shiny metals with various industrial purposes. Like the transition metals, they form cations with varying amounts of charge. Actinides are metals in the 5f part of the periodic table. Most are radioactive and man-made. Uses of these elements are primarily in the generation of nuclear power or in nuclear explosives. Small amounts of elements such as americium are used in smoke detectors. Chalcogens are group 16 in the periodic table. Starting with oxygen, these elements are mostly nonmetallic and somewhat electronegative, forming ions with a -2 charge. Halogens are group 17 in the periodic table. These elements are highly reactive oxidizers, and all form ions with a -1 charge. All are electronegative. All are also extremely dangerous, especially when inhaled. Noble gases are group 18 in the periodic table. They basically don't react with anything because they have a stable octet. They used to be called the inert gases, but it was found a while back that some can form somewhat unstable compounds with halogens and oxygen. 6

Elements Therefore…. Elemental Symbol Atomic # of a neutral element Protons + Neutrons = Mass # Mass # - Atomic # = Neutrons Elemental Symbol Unique one/two letter symbol Atomic # of a neutral element Equals the # of protons AND the # of electrons Unique for each element Atomic Mass #- Avg. mass of an atom of the element (AMU) Equals the SUM of protons and neutrons AMU=Atomic Mass Unit

The Nucleus Middle of the atom (central core) Holds positive charged protons and neutral neutrons Positively charged Contains most of the mass of the atom

The Protons All atoms of a given element have the same number of protons #of protons = the atomic number # of protons (+’s) = # of electrons (-’s) (in a neutral atom)

The Neutrons The number varies slightly among atoms of the same element Different number of neutrons produces isotopes of the same element

Isotopes \ Isomers Isotopes = an element with the same # protons, but different # neutrons Ex: C-12 vs. C-14 Isomers = compounds with the same molecular formula, but different structures

Practice Problems! How many protons does a sodium (Na) atom have? How many neutrons does a fluorine (F) atom have? What is the atomic mass for oxygen (O)? What is the atomic number for phosphorus (P)?

The Electrons Negatively charged high energy particles with little or no mass Travel at very high speeds in different energy levels Energy levels are different distances from the nucleus

Electron Shell Electron Shell Atomic # = 6  6 total electrons Shells: Inner most  can hold at most 2 e- Outer most  can hold at most 8 e- Third outer most  can hold at most 8 e- Elements want to have full shells, because this makes them stable! The electrons on the most outer shell is called VALENCE electrons EXAMPLE: Carbon (neutral) Atomic # = 6  6 total electrons 2 electrons fill the inner most shell 4 will be in the outer most shell This means Carbon has 4 VALENCE electrons Can bond to 4 other atoms!

Periodic Table Elements are arranged by their atomic number on the Periodic Table The horizontal rows are called Periods & tell the number of energy levels Vertical groups are called Families & tell the outermost number of electrons

Molecules and Compounds Molecules – 2+ atoms bonded together – O2 for Oxygen Compound – 2+ elements bonded together - CO2 for carbon dioxide and NaCl for sodium chloride Water is a molecule because it is made from atoms that have been chemically combined. It is also a compound because the atoms that make water are not all the same - some are oxygen and some are hydrogen. Oxygen in the atmosphere is a molecule because it is made from two atoms of oxygen.

Compounds Compounds : Examples Have different properties than individual elements Ex: NaCl = 1 sodium + 1 chloride  table salt Ex: H20 = 2 hydrogen + 1 oxygen  water Ex: NaOH = 1 sodium + 1 oxygen + 1 hydrogen Ex: CO2 = 1 carbon + 2 oxygen

Compounds What happens when the ratio of atoms changes? H20 vs. H2O2 When the ratio of elements in a compound changes, the physical and chemical properties change too

Molecules Molecule is two or more atoms held together by covalent bonds. Almost all of the substances that make up organisms, from lipids to nucleic acids to water, are molecules held together by covalent bonds. A compound is a type of molecule. All compounds are molecules, but all molecules are NOT compounds. Molecule Examples: H2O, O2, O3 Compound Examples: NaCl, H2O

Bonds Molecular “glue” Holds atoms together to form compounds Valence electrons are involved in bonding Valence electrons = electrons on outer most energy level. Atoms are most stable when their outer most energy level is filled

Bonding What holds atoms together? Atoms are held together by chemical bonds Goal: to fill outer electron shell…so atoms BOND together (share or give away/take electrons) to get a full outer shell 3 main types: Ionic bonds Covalent bonds Hydrogen bonds

Covalent Bonding Formed when two atoms SHARE one or more pairs of electrons. (‘co’ means ‘together’) When two or more atoms are joined by covalent bonds, we call this a molecule Covalent bonds are Very strong

Because positive and negative electrical charges attract each other ionic bonds form

Ionic Bonds Formed when one or more electrons are transferred from one atom to another Atoms lose or gain electrons If an atom loses electrons  becomes positively charged (+) If an atom gains electrons  becomes negatively charged (-) Atoms that have gained or have lost electrons are ions Ex: Salt (NaCl)

Cations & Anions Cation = when an atom loses an electron, it becomes more positively charged Positive Ion = Cation Remember: Cats have PAWS and are POSITIVE Ex: Removing an electron from a K (potassium) atom will….create a POSTITIVE ION = CATION Anion = When an atom gains an electron, it becomes more negatively charged Negative Ion = Anion Ex: If a Cl (chlorine) atom gains an electron…creates a NEGATIVE ION = ANION

States of Matter Atoms are in constant motion (called kinetic energy) The rate at which atoms or molecules in a substance move determines its state

Level of Organization Subatomic particles (p+, e-, n0) atom (O) Element (O) molecule (O2) macromolecules (lipid) Cell (blood cell) <--life begins here Tissue (epithelia tissue) Organ (lung) Organ system (Respiratory System) Organism (Panthera leo (lion))