Presentation on theme: "Bellringer – November 12, 2014 Look at the Periodic Table:"— Presentation transcript:
1 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!
2 Introduction to Chemistry Honors Biology Ms. Kim
3 Composition of MatterMatter - everything in universe is composed of matter (“stuff”)Matter is anything that occupies space or has massMass – quantity of matter an object hasWeight – pull of gravity on an object
4 Chemistry of LifeAll 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.
5 Atomic StructureEach 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 nucleusNeutrons (0) in nucleusElectrons (-) in a cloud outside!
6 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- SulfurCHNOPSThe 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 periodsRow = Period. Hydrogen and helium are in period one.Groups =ColumnsThe 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 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
7 Elements Therefore…. Elemental Symbol Atomic # of a neutral element Protons + Neutrons = Mass #Mass # - Atomic # = NeutronsElemental SymbolUnique one/two letter symbolAtomic # of a neutral elementEquals the # of protons AND the # of electronsUnique for each elementAtomic Mass #-Avg. mass of an atom of the element (AMU)Equals the SUM of protons and neutronsAMU=Atomic Mass Unit
8 The Nucleus Middle of the atom (central core) Holds positive charged protons and neutral neutronsPositively chargedContains most of the mass of the atom
9 The ProtonsAll 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)
10 The NeutronsThe number varies slightly among atoms of the same elementDifferent number of neutrons produces isotopes of the same element
11 Isotopes \ IsomersIsotopes = an element with the same # protons, but different # neutronsEx: C-12 vs. C-14Isomers = compounds with the same molecular formula, but different structures
12 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)?
13 The ElectronsNegatively charged high energy particles with little or no massTravel at very high speeds in different energy levelsEnergy levels are different distances from the nucleus
14 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 electronsEXAMPLE: Carbon (neutral)Atomic # = 6 6 total electrons2 electrons fill the inner most shell4 will be in the outer most shellThis means Carbon has 4 VALENCE electronsCan bond to 4 other atoms!
15 Periodic TableElements are arranged by their atomic number on the Periodic TableThe horizontal rows are called Periods & tell the number of energy levelsVertical groups are called Families & tell the outermost number of electrons
17 Molecules and Compounds Molecules – 2+ atoms bonded together – O2 for OxygenCompound – 2+ elements bonded together - CO2 for carbon dioxide and NaCl for sodium chlorideWater 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.
19 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
20 MoleculesMolecule 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, O3Compound Examples: NaCl, H2O
21 BondsMolecular “glue”Holds atoms together to form compoundsValence electrons are involved in bondingValence electrons = electrons on outer most energy level.Atoms are most stable when their outer most energy level is filled
22 Bonding What holds atoms together? Atoms are held together by chemical bondsGoal: to fill outer electron shell…so atoms BOND together (share or give away/take electrons) to get a full outer shell3 main types:Ionic bondsCovalent bondsHydrogen bonds
23 Covalent BondingFormed 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 moleculeCovalent bonds are Very strong
25 Because positive and negative electrical charges attract each other ionic bonds form
26 Ionic BondsFormed when one or more electrons are transferred from one atom to anotherAtoms lose or gain electronsIf an atom loses electrons becomes positively charged (+)If an atom gains electrons becomes negatively charged (-)Atoms that have gained or have lost electrons are ionsEx: Salt (NaCl)
27 Cations & AnionsCation = when an atom loses an electron, it becomes more positively chargedPositive Ion = CationRemember: Cats have PAWS and are POSITIVEEx: Removing an electron from a K (potassium) atom will….create a POSTITIVE ION = CATIONAnion = When an atom gains an electron, it becomes more negatively chargedNegative Ion = AnionEx: If a Cl (chlorine) atom gains an electron…creates a NEGATIVE ION = ANION
28 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
29 Level of Organization Subatomic particles (p+, e-, n0) atom (O) Element (O)molecule (O2)macromolecules (lipid)Cell (blood cell) <--life begins hereTissue (epithelia tissue)Organ (lung)Organ system (Respiratory System)Organism (Panthera leo (lion))