Chapter 2 and Atlas 2: Chemistry of Life Flashcards
What is an element?
Simplest form of matter to have chemical properties. Each identified by atomic number (number of protons in nucleus).
What is an atom?
Nucleus composed of protons (single positive charge, P+) and neutrons (no charge, N0).
Around nucleus are electrons (single negative charge, E-) in electron shells (first, second, and third level energy). More energy electron has, farther away from nucleus.
What is an isotope?
Same number protons, different number neutrons. Unstable isotopes are called radioisotopes, and process of decay is radioactivity.
What is ionizing radiation?
Destroys molecules and produces dangerous free radicals and ions in human tissue.
Physical half-life vs Biological half-life
Physical: time required for 50% of atoms to decay to a more stable isotope.
Biological half life: time required for half of it to disappear from body.
What is an ion?
charged particle with unequal number of protons and electrons. Consists of single atom with positive or negative charge, group of atoms, or a molecule.
What is ionization?
The giving up of electrons to fill valence shell, forming ions.
What is an anion vs cation?
Anion: Particle that gains electrons acquires negative charge.
Cation: Particle that loses electrons acquires positive charge because of extra protons.
What is an anion vs cation?
Anion: Particle that gains electrons acquires negative charge.
Cation: Particle that loses electrons acquires positive charge because of extra protons.
What is an electrolyte?
Acids, bases, or salts that ionize in water and form solutions that conduct electricity.
What is a free radical?
Unstable, highly reactive chemical particles with an odd number of electrons.
Added dot at the end of element represents extra electron.
What is an antioxidant?
Chemical neutralizes free radicals.
What is a molecule?
Chemical particle with two or more atoms united by chemical bond.
Molecules composed of two or more elements are called compounds. (CO2)
What is an isomer?
Two molecules with the same molecular formulae but different arrangements of atoms.
What is covalent bond?
Formed by the sharing of valence electrons. (H2)
Single covalent bond: sharing of single electron.
Double covalent bond: Sharing of two pairs of electrons. (0=C=0)
Polar vs Nonpolar Covalent bonds
Polar: two atoms share electrons unequally.
Non polar: Two atoms share electrons equally.
Hydrogen Bonds
Weak attraction between positive hydrogen atom and a negative oxygen/nitrogen atom.
Van der Waals Forces
Weak, brief attraction between neutral atoms. Important in protein folding, binding of proteins and lipids.