Chapter 2.1 Flashcards
Element
The simplest form of matter to have unique chemical properties.
(An atom is the smallest amount of an element)
Atom
The smallest amount of an element; Can’t be further divided
Made of protons, neutrons, and electrons
Molecule
Two or more atoms that are chemically joined together
Compound
A substance that contains more than one element
Covalent bond
Atoms bonded by sharing electrons
Ionic bond
Electrons completely transferring from one atom to another
Six most abundant elements in the human body
- O - Oxygen 65%
- C - carbon 18%
3. H - Hydrogen 10% - N - Nitrogen 3%
- Ca - Calcium 1.5%
- P - Phosphorus one percent
Six lesser elements of the human body
- S - Sulphur
- K - potassium
- Na - Sodium
- Cl - Chlorine
- Mg - Magnesium
- Fe - Iron
Structure of an atom
 nucleus at the center made of protons (p+) And neutrons (n0), Surrounded by one or more clouds of electrons on electron shells
Atomic mass
Atomic mass = Proton+neutron
Proton
A single positive charge that weighs approximately one atomic mass unit
Neutron
Has no charge, weighs approximately one atomic mass unit
Electrons
Tiny particles with a single negative charge and very low mass. They determine the chemical properties of an atom.
Electron shells (energy levels)
Where are electrons swarm about the nucleus in concentric regions.
In atoms dealing with human physiology there are not more than four
Valence electrons
Electrons of the outer most shell.
Determine the chemical bonding properties of an atom
Isotopes
Variety of the same element that differ from one another only in number of neutrons – so also atomic mass. Behave the same chemically
Deuterium
Isotope of hydrogen atom with one proton one neutron (2H)
Tritium
Isotope of Hydrogen atom with one proton and two neutrons (3H)
Atomic weight
Relative atomic mass: accounts for the fact that an element is a mixture of isotopes, so slightly different than atomic mass
Radioisotopes
Unstable isotopes that decay two more stable isotopes by giving off radiation
Radioactivity
The process of decay of unstable isotopes
Ionizing radiation
High energy radiation eject electrons and energy from atoms, converting atoms to ions
Ions Destroy molecules and produces dangerous free radicals and ions in human tissues
A High dose of ionizing radiation is
Fatal
In lower doses of ionizing radiation, it can be what?
Mutagenic – causing mutations in DNA
Carcinogenic Dash triggering cancer as a result of mutation
Examples of ionizing radiation
Ultraviolet raise, x-rays, and alpha beta and gamma particles produced by nuclear decay
Alpha particle
Two protons, two neutrons, too large to penetrate skin, but dangerous when emitted by radioisotopes that have gotten into the body
Beta particle
A free electron. 
How do isotopes of the same element differ from each other?
They have a different number of neutrons so a different atomic mass
How do radioisotopes differ from other isotopes?
They are unstable isotopes and decay to more stable isotopes by giving off radiation
Clinical relevance of ionizing radiation
It destroys molecules and produces dangerous free radicals and ions in human tissues. can be fatal in high doses. In low-doses it can be Mutagenic in carcinogenic
Ex:Strontium 90 released by nuclear accidents settles onto pastures and contaminates cows milk. In the body behaves complete like calcium, becoming incorporated into the bones, where it emits beta particles for years.
Three forms of ionizing radiation
Ultraviolet rays, x-rays, and radiation produced by nuclear decay: alpha particles beta particles and gamma rays
Difference between the physical and biological half-life of a radio isotope
Physical half-life: time required for 50% of Adams to decay two more stable isotope
Biological half-life: time required for half of it to disappeared from the body by radioactive decay and excretion
Clinical relevance of difference between physical and biological half life
Physical half-lives can be really really long. Biological half life’s can be much shorter because they exit the body
The difference between an ion and an atom is:
Atoms are neutral particle; ions are positively or negatively charged particle
How ions form
Elements with 1-3valence electrons give them up, and those with 4-7 electrons gain more. If an atom of the first kind is exposed to an atom of the second, electrons may transfer from one to the other and turn them both into ions (ionization)
Two types of ions are:
Anion: the particle that GAINS electrons=negative charge
Cation: The particle that LOSES electrons= positive charge
Example of anion
Sodium (Na) and chlorine (Cl) meet. One electron transfers from Na to Cl, producing a chloride ion with a unit negative charge (Cl-)
Example of cation
Sodium (Na) and chlorine (Cl) meet. One electron transfers from Na to Cl, producing a sodium ion with a unit positive charge (Na+)
How electrolytes differ from atoms and ions
Electrolytes are the chemical compounds from which ions are made
(Chemical compound that produces ions when it is dissolved in water)
Most common electrolytes
Sodium (Na) Potassium (K) Chloride (Cl) Bicarbonate (HCO3) Calcium (Ca) Phosphorus (P)
Functions and medical relevance of electrolytes
- Can detect electrical activity of muscles, heart, brain because electrolytes conduct electrical currents from organs to skin surface
- Imbalance Can cause cramps, brittle bones, coma, cardiac arrest.
- Electrolytes Important for:
- Chemical reactivity
- Osmosis effects
- Electrical effects
Free radical
Unstable, highly reactive chemical particles with an odd number of electrons.
Produced by: Some normal metabolic reactions, radiation, chemical such as nitrates.
Ex: superoxide anion O2-• —>dot symbolizes odd electron
Medical relevance of free radicals
They quickly combine with molecules such as fats proteins and DNA, converting them into free radicals and triggering chain reactions to destroy more molecules. Ex: Free radicals can cause some forms of cancer and myocardial infarction (death of heart tissue)
Molecule versus compound
Molecules: chemical particles composed of two or more atoms united by a chemical bond, either same or different.
Compound: molecules composed of two or more Different elements
Isomers
Molecules with identical molecular formulae but different arrangements of their atoms.
Ex: ethanol and ethyl ether
Ethanol: MF: C2H6O, SF: CH3CH2OH
Ethyl Ether: MF: C2H6O SF: CH3OCH3
How to determine a molecules molecular weight
Sum of the atomic weights of its atoms. Needed to compute measures of concentration
What is the nature and distinguishing characteristics of ionic bonds
Relatively weak attraction between an anion and a cation. Easily disrupted in water as when salt dissolves
Covalent bond and types
Sharing of one or more pairs of electrons between nuclei
- Single covalent
- Double covalent
- Triple covalent
And
-Nonpolar covalent
-Polar covalent
 Single covalent bond
Sharing of one electron pair
Double covalent bond
Sharing of two electron pairs.
Ex: carbon atoms
carbon and oxygen atoms
carbon and nitrogen atoms
Nonpolar covalent
Covalent bond in which electrons are equally attracted to both nuclei.
Polar covalent bond
Electrons are more attracted to one nucleus than the other, resulting in slightly positive and negative regions in one molecule. Maybe single or double
Hydrogen bond
Weak attraction between polarized molecules or between polarized regions of the same molecule. important in a three-dimensional folding and coiling of large molecules. Easily disrupted by temperature and pH changes
Van der waals force
Week, brief attraction due to random disturbances in the electron clouds of adjacent Adams. We just of all bonds individually, but can have strong effects collectively
Polar covalent bonds give rise to hydrogen bonds how?
When hydrogen bonds with oxygen the electrons are more attracted to the oxygen nucleus in orbit more than they do the hydrogen. This makes the oxygen region of the molecule slightly negative in the hydrogen region slightly positive
