An atom is the smallest unit of matter that retains the attributes and characteristics of its element.
The number of protons (p+) and neutrons (n˚) are always the same; the charges balance each other out which gives the atom an electrically neutral charge (no charge).
What are subatomic particles?
What make up atoms.
There are dozens of subatomic particles.
Only 3 are important in the understanding of the bodies chemical reactions.
What is a neutron? (n˚)
Part of an atoms nucleus.
Has no charge (neutral).
What is a proton? (p+)
Part of an atoms nucleus.
Has a positive charge.
Atoms always have the same number of protons as electrons.
What is an electron (e-)
Envelops the nucleus of an atom while moving around it in shells called electron shells.
The electron shells have a capacity of 2, 8, then 18.
Has a negative charge.
Atoms have the same number of protons as electrons.
What is an atoms atomic number?
The number of protons that appear in the atoms nucleus.
Each element has its own atomic number.
What is an isotope.
An atom with a deviating number of neutrons from the average of its element.
Isotopes are referred to by their protons and neutrons, as in Iodine-131 (53 protons and 78 neutrons), or carbon-12 (6 protons and 6 neutrons).
Most isotopes are stable (their nuclei do not decay into a stable structure.
An isotope will have the same number of protons as other atoms of its element, which means the same number of electrons.
An isotope will retain its elements chemical properties because it keeps the same number of electrons.
What is a radioactive isotope?
An unstable isotope (atom of element with differing # of neutrons) whose nucleus decays into a stable form, often into a different element.
Radiation in the form of subatomic particles or packets of energy is released during this decay.
Decay can be a fraction of second, or million years.
What is a half-life?
The half-life of an isotope is the time required for half of the radioactive atoms in a sample of that isotope to decay into a more stable form.
What is an atoms atomic mass (atomic weight) and what is used to measure it?
The average mass of all the naturally occurring isotopes of an element.
The standard unit for measuring atomic mass is a dalton, known as an atomic mass unit (amu).
The atomic mass is usually close to the mass number sense neutrons have a mass of 1.008 daltons, protons have a mass of 1.007 daltons, and electrons have 0.0005 daltons.
What is an ion?
When an atom or molecule gains or looses an electron it becomes an ion (process called ionization). Ions have a positive or negative charge sense the (p+) and (e-) do not balance each other out to neutral.
Ca^2+ is a calcium ion with 2 positive charges, Ca^1- would be a calcium ion with 1 negative charge.
What is a molecule?
A molecule is when 2 or more atoms share electrons. This is called an atomic bond.
Molecules are neutral and are hold together by covalent bonds.
A molecule can be formed of 2 atoms of the same element, or 2 different ones.
What is a compound?
A substance (molecule) with two or more different elements such as NaCl, or H2O (H2O, 2 should be a subscript describing the number of atoms of that element).
Compounds have different properties than those of their individual elements.
What is a free radical?
An atom or molecule with an unpaired electron in the outer electron shell (valence shell).
Highly reactive and unstable.
Becomes stable by giving up or taking an electron from another molecule. But in the process creates another free radical.
Antioxidants inactivate free radicals by giving an electron but not becoming free radicals.
What are a few differences between ions and free radicals?
Ions have a charge( either positive or negative) whereas Free Radicals are usually neutral.
Ions have completed their valance shell though chemical[covalent] bonding( either though the octet or duplet rule) while the valance shell of free radicals is incomplete.
Ions have an even number of electrons whereas free radicals have an odd number of electrons.
Ions are represented with a "-" or "+" in the superscript while free radicals have a dot(.) above them for the unpaired electron.
What are the dangers of free radicals? What are some diseases they are thought to contribute to?
Free radicals tear apart other atoms and molecules to gain or loose their unpaired electron, which leaves those atoms or molecules needing to do the same thing. This can cause chain reactions so to speak.
Free radicals can contribute to diabetes mellitus, Alzheimer's disease, macular degeneration, cataracts, cancer, atherosclerosis, emphysema, rheumatoid arthritis, and deterioration associated with aging.