Chapter 2 Flashcards
Ionic bond
An atom with an electric charge
One atom is the electron donor (loses electron), one an electron acceptor
Cation (lost negative electron) = POSITIVE charge
Anion (gained negative electron =more negative) = Negative charge
Example is sodium chloride
Opposites attract
Covalent bond
Strong bond involving shared electrons
If sharing one pair of electrons =single
If sharing two pair= double. Etc
Polar =unequal sharing of electrons, one atom has a stronger electronegativity (water)
Nonpolar= equal sharing of electrons between atoms that have equal pull
Hydrogen bond
Weak polar bond
In water causes surface tension (cohesion)
Matter exists in 3 states …
Solids, liquids, gases
Elements in the body
26 different chemical elements are normally found in the body.
Only four of those are considered “major elements” and constitute 96% of the body’s mass.
Oxygen, carbon, hydrogen, and nitrogen
8 others the “lessers” =3.6%
Calcium, phosphorus, potassium, sultry, sodium, chlorine, magnesium, and iron.
Atom
Smallest units of matter. Hydrogen atoms are the smallest atoms.
How many electrons can each shell hold?
First shell: 2
Second shell: 8
Third shell: 18
How do you determine the atomic number of an element?
By the amount of protons in its nucleus.
How do you determine the mass number of an atom?
It’s the sun of protons and neutrons.
Isotopes
Have a different number of neutrons than protons.
For example. In a sample of oxygen. Some atoms have 9 or 10 neutrons- but ALL HAVE 8 electrons and protons. The mass number determines the name of the isotope. For example (oxygen) O16 O17 O18
Ion
Is an atom that has a positive or negative charge because it has an uneven number of protons and electrons.
Molecule
When two or more atoms share electron(s). A molecule may include two atoms of the same kind. For example oxygen O2
Compound
Is a substance that contains atoms of two or more different elements. Most of the atoms in the body are joined into compounds.
Free radical
Is an atom or group of atoms with an unpaired electrons in the outer most shell. Example is superoxide which is the addition of an electron to an oxygen molecule.
Having an unpaired electron makes a free radical unstable, highly reactive, and destructive to nearby molecules.
Free radicals become stable by giving up their extra electron or pairing with an electron from another molecule, making them able to break apart important body molecules.
Octet rule
One atom is more likely to interact with another atom if it leaves both atoms with eight valence electrons.
Where are ionic bonds mostly found in the body?
Teeth and bones. Where they give great strength.
Electrolyte
An ionic compound that breaks apart into positive and negative ions in a solution.
Ions
Have a charge associated with them. For example if written as H+ (it’s because it donated its electron and gave up negativity)
Electonegativity
The power to attract electrons to itself (atom)