Chapter 2: Chemistry of Life Objects Flashcards
charge of protons
postive charge
location of protons
in the central core of atom (atomic nucleus)
charge of neutrons
no charge
location of neutrons
in the atomic nucleus, slightly larger than protons
charge of electrons
negatively charged
location of electrons
outside atomic nucleus
The bulk of an atom’s mass comes from its ___ and ___
protons and neutrons
The first electron shell, which is closet to the nucleus, can hold __ electrons
2
The second electron shell can hold __ electrons
8
The third electron shell can hold ___ electrons (but is “satisfied” with only __)
18, 8
Element
a substance that cannot be broken down into simpler substance by chemical means
Atomic number
number of protons in the atomic nucleus; defines every element.
Human body is made up of four major elements
hydrogen, oxygen, carbon, nitrogen
Mass number
equal to sum all protons and neutrons in atomic nucleus
Isotopes
atoms with the same atomic numbers but different mass number
how isotopes are produced by changing the relative number of a specific subatomic particle
isotopes have the same atomic number but different mass numbers, which means the neutrons are changed.
Atom
smallest unit of matter that retains original properies
radioisotopes
unstable isotopes; high energy or radiation released by radioactive decay; allows isotope to assume more stable form
three basic types of mixtures
suspensions, colloids, solutions
Suspension
particles large and usually visible; settle out
Colloid
two distinct components; particles small and not visible; do not settle out
Solution
particles extremely small and not visible; do not settle out; one component dissolves in the other component
Solute
substance dissolved
Solvent
substance that dissolves solute
Chemical bonds are formed when ___ of atoms interact.
valence electrons (outermost shell)
Valence electrons determine how an atom interacts with other atoms; whether it will ____ with specific atom
form bonds
Octet rule
atom is most stable when 8 electrons in valence electron.
Duet rule
atoms with 5 or fewer electrons - atom is most stable when valence electron holds 2 electrons
Ionic bond
electrons are transferred from metal atom to nonmetal atom
2 formation of ions
cations and anions
cation
positively charged ion; metal loses one or more electrons
anion
negatively charged ion; nonmetal gains one or more electrons
attraction between opposite charge bonds ions to one another forming ___
salt
Covalent bonds
strongest bond; two or more nonmetals share electrons
Two atoms can share one (___), two (____), three (____)
single bond, double bond, triple bond
Nonpolar covalent bond
two non metals in molecule with similar or identical ectronegativities pull with equal force; share electrons equally
Nonpolar molecules occur in 3 situations
atoms sharing electrons are same element
arrangement of atoms makes one atom unable to pull more strongly than another atom
bond is between carbon and hydrogen
Nonpolar covalent bond- H2 (hydrogen molecule):
Electrons spend equal time around the two hydrogen atoms.
Polar covalent bond
nonmetal with different electronegativites share electrons unequally; form polar molecules
atom with ___ electronegativity becomes partially negative, pulls shared electrons close to itself
higher
atom with ___ electronegativity becomes partially positive; shared electrons are pulled toward other atom
lower
Dipoles
polar molecules with partially positive and partially negative ends
polar covalent bond–H20 (water)
electrons spend more time around the more electronegative oxygen atom
Hydrogen bonds
weak attractions between partially positive end of one dipole and partially negative end of another dipole
Surface tension
responsible for key property of water
____ water molecules are more strongly attracted to one another than to ____ air molecules at surface.
polar, nonpolar
hydrogen bonds between water molecule create surface tension that causes ___
blood to form droplets
