BIO 100 Cincinnati State

Chapter #2 Lecture pp 12-29Science, Atoms, Elements, & Subatomic Particles

Lecture Presentations for Integrated Biology and Skills for Success in ScienceBanks, Montoya, Johns, & Eveslage

Guiding Principles for the CourseLooking at seemingly simple things deeply

Conceptual understanding

Practical Applications

Contextualized Some of the material may appear to be simple. The trick is to gain a deep conceptual understanding of the process, then you can apply it to complex situations with ease. We will be taking seemingly simple processes and putting them into new situations. When someone does not have a strong foundation to stand on, problems can arise when facing challenges. This course will provide to you the tools you will need to understand many of the complex concepts found in the biological world.2Chapter #2 Learning Objectives By the end of the lecture today, students will be able to:List and define the typical stages in the scientific method.Compare and contrast inductive versus deductive reasoning.Compare and contrast mass versus weight as scientific valuesDetermine the mass of an atom when given the subatomic particles.Define and describe chemistry terms such as element, subatomic particle, proton, neutron, electron, atomic number and atomic mass.Define isotopes and describe differences between isotopes of an element.List the most abundant elements found in the human body.Distinguish the role of valence electrons in chemical reactionsIdentify and describe any general trends that can be observed in the periodic table of elements including but not limited to atomic mass, ionization energies, and electronegativity values.

Scientific MethodThe Scientific Method involves a series of steps that are used to investigate a natural occurrenceIt is important to develop a deep understanding of this approach to science as it is a universal way of looking at problems, situations, and phenomena in nature Please become familiar with the flowchart presented here and in your text

Deductive vs. Inductive Logic It is very important to define the differences between the two major types of logic that will be used to drive the scientific method in your future observations of natureDeductive logic starts with a statement believed to be true and then goes on to predict what facts would also have to be true to be compatible with that statementIn contrast, inductive logic involves taking observations of facts and creating a new theory that is compatible with those observations of facts

5Control vs. Comparative ExperimentsThere are two main types of experiments used in science: The Controlled Experiment and The Comparative ExperimentThe purpose of a controlled science experiment is to find out what happens to something if you change something else while you keep all other things unchangedIn a controlled experiment you can test only one independent variableThis means that you can change only one condition in your experimentThe purpose of a comparative experiment is to compare the effect of two or more different things on somethingIn a comparative experiment you can test the effect of a few independent variables but not in the same experimental group where also only one independent variable is allowed as in the case of a controlled experiment

What is Biochemistry??Life is all about the multitude of biochemical reactions that take place all day every dayEach part of every living organism is biochemically connectedBiochemistry is defined as the study of life on a molecular levelBiochemistry covers the biochemical bonds linking atoms to form simple molecular structures and larger structures like DNA, which holds genetic information which flows into RNA and eventually proteinsBiochemistry is all about discovering new biochemical structures and determining their functions and interactions with other moleculesBiochemistry deals with complex molecular machines, metabolic pathways, and biochemical communications within and in-between organisms

The Chemical ElementsElement - simplest form of matter to have unique chemical propertiesAtomic number of an element - number of protons in its nucleusperiodic table elements arranged by atomic numberelements represented by one- or two letter symbols24 elements have biological role6 elements = 98.5% of body weightoxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus trace elements in minute amounts1010

Atomic StructureNucleus - center of atomprotons: single + charge, mass = 1 amu (atomic mass unit)neutrons: no charge, mass = 1 amuAtomic Mass of an element is approximately equal to its total number of protons and neutronsElectrons in concentric clouds that surround the nucleuselectrons: single negative charge, very low massdetermine the chemical properties of an atomthe atom is electrically neutral because number of electrons is equal to the number of protonsvalence electrons in the outermost shelldetermine chemical bonding properties of an atom

IsotopesElements are defined by the number of protons in an atom's nucleusFor example, an atom with 6 protons must be carbon, and an atom with 92 protons must be uraniumAtoms of the same element can have different numbers of neutrons; the different possible versions of each element are called isotopesFor example, the most common isotope of hydrogen has no neutrons at all; there's also a hydrogen isotope called deuterium, with one neutron, and another, tritium, with two neutrons.

15Electron Energy ShellsThe Bohr Model shows all of the particles in the atomIn the center is circles. Each circle represents a single neutron or protonProtons should have a plus or P written on them Neutrons should be blank or have an NIn a circle around the nucleus are the electrons. Electrons should have a minus sign or an e

16Electrons have special rules that they must followYou cant just shove all of the electrons into the first orbit of an electronElectrons live in something called shells or energy levels. Only so many can be in any certain shell.

Nucleus 1st Energy Shell2nd Energy Shell3rd Energy Shell 17The electrons in the outer most shell of any element are called valance electronsThe electrons that are more loosely held by the nucleus (the valence electrons, those furthest away from the nucleus) are the ones that are gained, lost, or shared during chemical reactionsThis is why it is so important to learn and understand about valence electrons

So lets try it.How to draw a Lithium atomFirst, look at the Periodic TableSecond, determine the number of protons (Look @ the atomic number)Then determine the number of neutrons (Atomic mass atomic number)Then determine the number of electrons (Look @ the atomic number)

3LiLithium7So lets try it.3LiLithium7+++Protons = 3Neutrons = 4(7-3=4)---Electrons = 3 2 in the 1st shell, 1 in the 2nd shellGeneral Trends of the Periodic TableA trend is a pattern or a repetition of particular propertiesTrends of the periodic table include:Atomic Mass, Atomic Radius, Net Nuclear Charge,Ion Size, Metallic or Non-Metallic Property, Electro-negativity, 1st ionization energyThe periodic table is arranged in a certain way to keep elements with similar properties close together

Groups vs. Periods Groups go up and downPeriods go left and rightGroups share many similaritiesPeriods show periodically (regularly) changing properties

The Alkali Metals are in Group 1 but Hydrogen is not in this group.

Alkaline Earth Metals are in Group 2

TRANSITIONAL METALSare in Groups 3 - 12

INNERTRANSITIONAL METALSare at the bottom and fit in as shown

NON-METALSare at the right hand side of the table

Noble Gasesare at the far right, group 18

First Trend-Atomic MassAtomic mass goes higher from element to element, with few exceptions The Group Trend is that atomic mass increasesThe Period Trend is that atomic mass increases tooBecause of specific properties, the Periodic Table has a non-regular shapeThe elements are arranged by properties rather than a way just make the table be uniform in shape

30Second Trend-Atom RadiusIf you follow along the periodic table for atomic radius, you find:The Group Trend for atomic radius is that it increases down a group.The Period Trend for atomic radius is that it decreases left to right.

SHOWS Atomic Sizes for Groups and Periods

Third Trend-1st Ionization Energy 1st ionization energy is the amount of energy needed to remove a valence electron from an entire mole of atoms and make them all into +1 ionsFor example To turn a mole of Li atoms into a mole of Li+1 ions, it would take 520 kJ/mole

FIRST IONIZATION ENERGY FOR SOME SELECTED ATOMSNa496 kJ/molMg736 kJ/molAl 578 kJ/molSi787 kJ/molP 1012 kJ/molGoing across the 3rd period, the trend for1st Ionization Energyis to INCREASE.

Fourth Trend Electronegativity Electronegativity is the amount of pull that an atom has for another electron in a bonding situationFluorine has the greatest desire of all atoms for that electron gainFluorine is given the rating of 4.0 on the E-N scale, the highest Electronegativity of all elementsGoing down a group the trend is towards LOWER E-N valuesGoing across a period the trend is towards higher E-N valuesIt is all about HOW CLOSE IS THE ATOM TO FLUORINE which determines the relative electro-negativity.

Exit Quiz1). Please illustrate and describe the importance of the typical steps that would show up in a flow chart depicting the scientific method.2). Compare and contrast the differences that exist between mass and weight in science.3). What are the three main subatomic particles? Be able to accurately assign mass, charge and location for each of these subatomic particles. 4). Define atomic number and atomic mass and be prepared to calculate each value. 5). What is the difference between an electron and a valence electron? Why are valence electrons so important?6). What is the difference between ionization energy and electronegativity? Are there any trends in the periodic table for these two values? What are they?