A&P Intro to chemistry (1) Flashcards
chemistry is
the science of the structure and interactions of matter
Atoms are
the smallest fundamental unit of life
subatomic particles are protons+ neutrons= electrons-
atoms are and individual unit of an element
h2o two elements, in a glass of water many atoms but still only two elements present
protons and neutrons are found in
the nucleus
electrons found in
shells
valence shell
aka “outermost shell” – this shell contains electrons that contribute to the reactive properties of the atom b/c they are either:
Donated
Received
Shared
the Octet rule
electrons with the atomic number under 20 strive to achieve 8 electrons in the valence shell
an isotope is
a variation of the same element due to a difference in its atomic mass (PROTON numbers are always the SAME, it’s the NEUTRONS that DIFFER.)
E.g. Hydrogen (H) has 1 proton & 1 electron in its most stable form. However if it has 1 neutron, it is now called deuterium, 2 neutrons => tritium. Some isotopes are highly unstable and therefore are prone to decaying which causes radioactivity (these are then called radioactive isotopes)
some substances such as uranium & plutonium are like this, and are often used in making WMD
free radicals are
atoms / molecules with an unpaired electron in its outermost shell.
E.g. Superoxide, hydrogen peroxide. These compounds are highly reactive and unstable and possess the capability to cause cellular damage.
free radicals2
Free radicals “steal” electrons from other cells by a process called “oxidation” thus causing cellular damage (in medical literature, this is termed OXIDATIVE STRESS)
ANTIOXIDANTS, such as vitamin E, carotene, lycopene, etc… help prevent this type of biochemical process.
FYI – many chronic diseases are the direct result or correlated with oxidative stress. E.g. macular degeneration, arthritis, Alzheimers, cancer…..to name a few.
ionic bonds
Ionic bonds- attraction between elements of OPPOSITE CHARGES when elements have lost or gained an electron. These are relatively strong when NOT in solution, but VERY weak when placed in solution.
tends to form between a metal and a non-metal
There are 2 categories of ions:
anion – negative charge (-‘ve) – elements that have gained electron (s)
cation – positive charge (+’ve) .. think cats make you feel positive….. prrrrrrrrrr. – elements that have lost electron (s)
The process of gaining or losing electrons is called ionization (as in ionizing radiation
when IONIC bonds are in water they become
electrolytes
covalent bonds are
when atoms SHARE electrons.
Very strong bonds. Also the most common type of bond that occurs in the body naturally.
Single = 1 pair, double = 2 pairs, triple = 3 pairs.
Covalent bonds have a tendency for POLARITY, (when 1 atom has a stronger attraction for the shared electrons than the other.
most common type of bond in the body
polar covalent bonds
polarity examples: the earth, batteries
when 2 atoms share the electrons un-equally (one atom has a stronger pull on the electrons therefore attracting it more than the other)
this property allows certain atoms greater ELECTRO-NEGATIVITY – the power to attract electrons to itself, more than the other element/atom within the same molecule
having polar bonds allows a molecule to have “POLARITY” (the property of one end being more negatively charged, and the other more positively charged) .. like a battery with opposite ends.
non polar covalent bonds
when 2 atoms share electrons equally (thus the electrons are found exactly in the middle between the 2 atoms)