ch 2: the chemistry of life PT 1

element

simplest form of matter to have unique chemical properties

atomic number

number of protons in the nucleus

⭐️electrons = to number of protons⭐️

6 naturally occurring elements

carbon, hydrogen, oxygen, calcium, nitrogen & phosphorus

CHOCNP

nucleus

-center of atom

-composed of protons & neutrons

atomic mass

protons + neutrons

protons

(p+) → single positive charge mass = 1 amu

neutrons

(n⁰) → mass (neutral) mass = 1 amu

⭐️-to find neutrons → atomic mass - atomic # ️

electrons

(e^-) → single negative charge

-in concentric clouds (electron shells or energy levels) surrounding nucleus (bonding)

an atom is electrically neutral as…

number of electrons = number of protons 😀

valence electrons

-in the outermost shell & determine chemical bonding properties of an atom

-interact during bonding⭐️

models of atomic structure - Bohr planetary model

😆

isotopes

-varieties of an element that have same # of protons but differ in the # of neutrons

-extra neurons increase atomic weight

ion

-a charged particle with unequal number of protons & electrons

-formed when an atom or molecule gains or looses electrons

ionization

transfer of electrons from one atom to another

anion

particle that has a net negative charge due to gain of electrons & fewer protons

cation

particle that has a net positive charge due to loss of electrons & more protons

molecular weight

sum of the atomic weights of its atoms

*leading # of atoms is from compound

*amu # is the atomic mass number

chemical bonding

-attraction between 2 or more atoms & hold atoms together within a molecule

-interaction of electrons

ionic bonds

-chemical attraction between oppositely charged ions, formed by the complete transfer of one or more electrons

attraction of a cation to an anion

covalent bonds

atoms share one or more pairs of valence electrons

*makes it organic

non polar covalent bond

electrons are shared equally

ex→ carbon atoms bonding together

polar covalent bond

electrons are shared unequally

ex → hydrogen bonding with oxygen, electrons spend more time by oxygen

hydrogen bond 💦💦💦💦💦💦💦💦💦💦💦

a weak attraction between a slightly positive hydrogen atom in one molecule & a slightly negative oxygen or nitrogen atom in another atom 💦

WATER & PROTEIN FOLDING️️

Van der Waals forces

weak, brief attractions between neutral atoms

acid

-a proton donor, releases H⁺ (hydrogen) ions in water

base

proton acceptor, accepts H⁺ ions or releases OH^- (hydroxide) ions in water

acidity is measured by…

PH SCALE

pH of 7.0 is neutral

pH of less than 7 is acidic

pH of greater than 7 is basic

blood = 7.35 & 7.45

energy

-the capacity to do work

“to do work” → means to move something, such as a muscle or a molecule

decomposition reactions

-large molecule breaks down into two or more smaller ones

AB → A + B

-CATABOLIC REACTION

COMP = CATA

synthesis reactions

-two or more small molecules combine to form a larger one

A + B → AB

-ANABOLIC REACTION

exchange reactions

-two molecules exchange atoms or group of atoms

AB + CD → AC +BD

catabolism

breaks down complex molecules into simpler ones

RELEASES ATP

anabolism

builds up & uses energy to build necessary molecules

CONSUMES ATP

calorie

-the base unit of heat

1 cal is the amount of heat to raise the temperature of 1g of water by 1°C

exergonic reaction

release energy, resulting in a negative change

EXIT ⬅

endergonic

require an input of energy, indicated by a positive change

ENTER ➡

hydrolysis

-chemical reaction where water is used to break down a compound into simpler molecules 💦

determinants of reaction rate

-concentration

-temperature rises

-surface area

-a catalyst is present (activation energy) → INVERSELY RELATED