* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Atoms
Survey
Document related concepts
Einsteinium wikipedia , lookup
Livermorium wikipedia , lookup
Abundance of the chemical elements wikipedia , lookup
Periodic table wikipedia , lookup
Valley of stability wikipedia , lookup
Isotopic labeling wikipedia , lookup
Chemical element wikipedia , lookup
History of molecular theory wikipedia , lookup
Transcript
RSPT 1060 MODULE B: Basic Chemistry Lesson #1 Atomic & Subatomic Matter Why Chemistry? • Respiratory Therapists must have a basic knowledge of the principles of chemistry … – To better understand the functioning of the human body – To better appreciate the clinical concepts of: • • • • Arterial blood gas interpretation Fluid and electrolyte physiology Nutrition Pharmacology Objectives • At the end of this module, the student will: – Define terms associated with atomic and sub-atomic matter. – Differentiate between the types of matter. – Describe what each item in an element’s box on the periodic table represents. – Compare the composition of the elements of the universe, the earth’s crust and the human body. – Differentiate between an atom, elements, molecules and compounds. Objectives • At the end of this module, the student will: – Describe the components of an atom and the purpose of each. – Differentiate between atomic number, atomic mass and mass number. – Explain what an isotope is. – Explain what determines physical and chemical properties of an element. Matter • What is Matter? – Anything that • Takes up space • Has mass (weight), and • Can be perceived by the senses. – If it’s “something” it’s matter, if it’s “nothing”, it’s not matter • The primary states of matter are: – Solid – Liquid – Gas Divisions of Matter Matter Pure Substance (Homogeneous) Mixture (Homogeneous or Heterogeneous) Elements Solution Compounds Suspension Colloid Matter - Pure Substances • Matter in it’s simplest form. – Atom, Element, Molecule, Compound • Always the same regardless of where it is found. – Oxygen (O), water (H2O), table salt (NaCl) • It cannot be broken down any further without a chemical or nuclear reaction. – It will then become a different substance. • Uranium in a nuclear bomb • Pure substances are homogenous. – Uniform in structure or composition throughout . Matter • So…what is an element or compound? Elements • An element is a pure form of matter. • Other pure forms of matter include: – Atoms – Molecules – Compounds Elements • Large collection of atoms of the same type. – Substance that cannot be broken down further and still maintain its identity. – All atoms have same atomic number. – Not bonded together, only existing together. • A listing of all the elements known to man is called the Periodic Table. Introduction to the Periodic Table 117 Elements 1 Atomic Number Hydrogen Element Name H Symbol or Abbrev. 1.01 Atomic Mass Unit (AMU) http://www.ceet.niu.edu/mrdl/software/Periodic%20Table.htm Elements of the Universe 91% of all atoms are Hydrogen 9% of all atoms are Helium The other 115 elements are found in traces. Elements of the Earth’s Crust 60.1% = 21.1% = 6.1% = 2.9% = 2.6% = 2.4% = 2.2% = 2.1% = oxygen silicon aluminum hydrogen calcium magnesium iron sodium Elements of the Human Body Major Water Macronutrients Micronutrients Elements •Hydrogen •Oxygen •Carbon •Nitrogen •66% of the body. •Calcium •Iron •Arsenic •Chlorine •Fluorine •Boron •Potassium •Cobalt •Copper •Phosphorus •Iodine •Manganese •Magnesium •Zinc •Molybdenum •Sulfur •Selenium •Chromium •Sodium •Silicon •Nickel Atoms • Smallest “particle” of an element. Molecule • Smallest “particle” of a pure substances (element or compound) bonded together. – Combination of similar atoms (O2 element) – Combination of different atoms (H2O compound) Compound • Substance composed of a large collection of molecules. Can be broken down by chemical means into molecules or elements. • Often will have properties unlike those of its constituent elements. Pure Substances A B Elements – A large collection of atoms of a given type. Atoms of element A Atoms of element B Atoms of element A&B existing together Molecules made from element A & B through a process called bonding. Compound – a large collection of molecules made from atoms from element A & B The Atom • Smallest particle of an element which still maintains the chemical properties of the element. • Head of a pin could hold 100 trillion atoms. The Atom • If broken down further by a nuclear reaction, an atom would become particles: – Electrons – Protons – Neutrons. The Atom • If broken down further, protons and neutrons are made of subatomic particles: – Positrons – Mesons – Neutrinos The Helium Atom Nucleus Proton 2 Protons (+) and 2 Neutrons (No Charge) 2ENeutron Electron Smallest particle of an element. Atom - Composition • Nucleus – Proton (+) nucleon – Neutron (No charge) nucleon Electron cloud or shell Electron (-) Atom - Nucleus • The nucleus is the small, dense positively charged center of the atom – It contains protons and neutrons (nucleons) – The nucleus only comprises 1/100,000 of the size of the atom even though it is constitutes the vast majority of the atom’s mass. Atoms - Nucleus • Nucleons – Protons • One Proton is 1836 times the size of an electron • The number of protons determines the atomic number. • The number of protons is always equal to the number of electrons – This allows for a neutral charge of the atom. – Neutrons • The number of neutrons can vary • The number of neutrons determines the number of isotopes an element will have. – Isotope: One of two or more atoms having the same atomic number but different mass numbers. Atom - Electrons • 99.9% of the atom is open space where the electrons travel (electron cloud or shell) – 99.99% of an atom is the negatively charged electron cloud – This cloud actually determines the size of the atom Atom - Electrons •Electrons do not contribute to the mass of the atom; only the size. EXAMPLE: If the electron cloud was the size of Ford Field, the nucleus would be smaller than a pea at the center of the field. •The nucleus determines the mass. Atom – Size & mass • Electrons determine size • Nucleus (protons & neutrons) determine mass Atom – Electron Number and Arrangement • The number and arrangement of the electrons determine the chemical properties of an element. – How it acts in relation to other elements – How it acts in a chemical reaction The Periodic Table 112 Elements 1 Atomic Number Hydrogen Element Name H Symbol or Abbrev. 1.01 Atomic Mass Unit (AMU) Atomic Number • The number of protons in the atom of a given element. • All atoms of an element have the same number of protons and electrons. – This never changes. • Because atoms are neutral, the atomic number also indicates the number of electrons. EXAMPLE: Boron has an Atomic # 5 5 protons & _____ 5 electrons This means there are _____ Atomic Mass Unit • Abbreviated as (amu). • Reflects the mass of the most frequently found form of an element in nature. • The unit amu is a unit of measure made up by scientists. • It is used as a unit of measure for a particle that is extremely small. – 1 amu = 1.6606 x 10-24 grams Mass of an Atom and the amu • The mass of an atom is too small to express in grams – Hydrogen atom = 1.7 x 10-24 gram. • The relative scale of atomic mass units is used instead of grams & scientific notation. Comparative Example • 12 eggs = One dozen • Dozen is a unit of measure made up by farmers. (not really) • Dozen is a simple unit of measure that represents a larger number (12) Mass of an Atom • Mass is composed mainly of the mass of protons & neutrons – Proton = 1 amu – Neutron = 1 amu Carbon and the amu • All elements are compared to the mass of carbon. – 1 amu = 1/12 the mass of a Carbon atom – Carbon has 6 protons & 6 neutrons – It’s atomic mass is 12.011 AMU • Carbon is a point of reference for all other elements – Hydrogen is 1/12 the mass of carbon so it has a mass of 1 amu • 1 proton & 0 neutron – Magnesium has twice the mass of carbon so it has a mass of 24 amu • 12 protons & 12 neutrons Isotope • There may be different forms of atoms of the same element. – This occurs when the number of neutrons varies. – Atoms of the same element with differing numbers of neutrons are called isotopes Isotopes and Physical Properties • Neutrons will determine the physical properties which vary slightly between isotopes. – Result: The same element may “appear” slightly different depending on which isotope you look at. All isotopes should “act” the same because the electron numbers don’t change. • Only 20 elements exist without isotopes. Isotopes and Medicine • We hear about isotopes most often in nuclear medicine. – Body scans use isotopes (Xenon) • Ventilation & perfusion of the lungs • Bone scans – Radioactive material is injected in the blood or inhaled into the lungs – Image forms on radiology film showing areas that isotope has been exposed to Key Facts about Isotopes • Isotopes: – Atoms of the same element – BUT, Have different numbers of neutrons • Atomic number on periodic table does not change (Same # of Protons) • Atomic Mass (amu) on periodic table does not change (Average of most common isotopes) • Mass number changes (Actual number of protons and neutrons) Example of an Isotope: Chlorine Example: Chlorine #17 Atomic mass 35.45 • Most common form (76% of the time) – Cl-35 with a mass of 34.97 amu • Less common form (24% of the time) – Cl-37 with a mass of 36.97 amu Calculation: – (0.76)(34.97) = 26.5772 amu – (0.24)(36.97) = 8.8727 amu 35.45 amu (average on periodic table) Isotope Chlorine: • Atomic mass – Atomic # = the average #neutrons • 35 – 17 = 18 neutrons in most common form Isotopes and Mass Number • “Mass Number” – Each isotope has its own mass number. – Not on the periodic table – Is the actual total number of protons + neutrons – The number of neutrons can change so the mass number can change. • Protons + Neutrons = Mass number Isotope Example: Chlorine #17 Atomic mass 35.45 • Most common form 76% of the time – – – – Cl-35 with a mass of 34.97 amu Mass # 35 Mass # - Atomic # = Neutrons 35 – 17 = 18 • Less common form 24% of the time – – – – Cl-37 with a mass of 36.97 amu Mass # 37 Mass # - Atomic # = Neutrons 37 – 17 = 20 Example: (K) Potassium • Atomic Number = 19 • Mass Number = 39 • Mass Number = 40 • Protons = _______ • Electrons = _________ • Neutrons = Mass # – Atomic # = ___________ or __________ Oxygen Isotopes (AMU 15.9994) Mass number 14 O 15 O 16 O Atomic number 8 8 8 Number of neutrons = (Mass # Atomic #) ? ? ? Number of protons & electrons ? ? ? Symbol ASSIGNMENTS • Read: Chemistry Book to assist in completing the objectives. • Self-Assessment