RSPT 1060MODULE 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 MatterMatter

Pure Substance

(Homogeneous)

Elements

Compounds

Solution

Suspension

Colloid

Mixture

(Homogeneous or

Heterogeneous)

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

Atomic Number

Element Name

Symbol or Abbrev.

Atomic Mass Unit (AMU)

1

Hydrogen

H

1.01

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% = oxygen21.1% = silicon6.1% = aluminum2.9% = hydrogen2.6% = calcium2.4% = magnesium2.2% = iron2.1% = sodium

Elements of the Human Body

Major Elements

Water Macronutrients Micronutrients

•Hydrogen•Oxygen•Carbon•Nitrogen

•66% of the body.

•Calcium

•Chlorine

•Potassium

•Phosphorus

•Magnesium

•Sulfur

•Sodium

•Iron

•Fluorine

•Cobalt

•Iodine

•Zinc

•Selenium

•Silicon

•Nickel

•Arsenic

•Boron

•Copper

•Manganese

•Molybdenum

•Chromium

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

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

B

A

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

2E-

Electron

Nucleus

Proton

Smallest particle of an element.

2 Protons (+) and 2 Neutrons (No Charge)

Neutron

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 sizedetermines 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 Table112 Elements

Atomic Number

Element Name

Symbol or Abbrev.

Atomic Mass Unit (AMU)

1

Hydrogen

H

1.01

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 This means there are _____ protons & _____ electrons

55 55

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

• 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

Carbon and the amu

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 isotopesisotopes

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: ChlorineExample: 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)

IsotopeChlorine:

• 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

IsotopeExample: 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: Potassium (K)• Atomic Number = 19• Mass Number = 39• Mass Number = 40

• Protons = _______• Electrons = _________• Neutrons = Mass # – Atomic #

= ___________ or __________

Oxygen Isotopes (AMU 15.9994)

Mass number

Symbol

Atomic number

14

O

8

15

O

8

16

O

8

Number of neutrons = (Mass # - Atomic #)

? ? ?

Number of protons & electrons

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ASSIGNMENTS

• Read: Chemistry Book to assist in completing the objectives.

• Self-Assessment