chp 2: the chemical basis of life

anything that takes up space and has mass

a measure of our energy content

carbon, hydrogen, nitrogen, oxygen

supernovas (explosion of stars)

made up of protons, neutrons, and electrons in an organized fashion

depends on the number of protons and neutrons in the nucleus

indicates the number of protons of an element

in the nucleus

outside the nucleus constantly moving in a cloud shape

protons and neutrons

electrons

determines the atomic number, which gives each element a unique identity

keeps the nuclei stable

responsible for how elements react

atoms of the same element with a different number of neutrons than protons in their nucleus that are unstable and emit radiation. the radiation is used for many medical procedures

have a differnt number of electrons than protons, and thus an electrical charge (charged atoms)

electrons

when two atoms are held together by the attraction between opposite charges

two atoms share electrons in order to have a completed outer shell

it holds atoms together. a lot of energy is needed to break them

O=O, the more lines there are the more bonds there are

weak interaction between hydrogen atom and highly electronegative atom

when two or more atoms are bonded covalently

if the molecule contains more than one element

molecules that participate in reactions (on left side)

molecules formed by reactions (on right side)

is a solvent, is cohesive and adhesive, has high surface tension, maintains a temperature compatible with life, as a solid it is less dense than as a liquid

70-90%

because of its high polarity and hydrogen bonding

ability of water molecules to cling together due to hydrogen bonding

ability of water molecules to cling to other polar surfaces

heat is released as sweat evaporates

steam has more heat absorbed from the vaporization and when it touches the skin it turns back to liquid and releases energy which leads to very severe burns

have high hydrogen ion (H^+) concentration

release hydroxide ions (OH^-)

the lower the pH the more acidic the solution, the higher the pH the more basic the solution. pH of 7 is considered neutral (like water).

important substances found in living organisms which help maintain a certain range of pH

it dissolves which releases free hydrogen ions that are then consumed which leads to decreased hydrogen ion activity. it acts as a buffer to stomach acid by consuming hydrogen ions