chemical basis of life

the basic unit of matter. It contains two regions

atom

the center of the atom that is formed from protons and neutrons

nucleus

the region outside of the nucleus

electron cloud

how many subatomic particles does the atom contain

3

how many subatomic particles are found in the nucleus

2

positively charged particles that have a mass of 1amu (atomic mass unit)

protons (p+)

neutral charge and also have a mass of 1 amu

neutrons (n+)

are the only particle found in the electron cloud (orbits)

electrons (e-)

electrons are _____________ charged particles

negatively

electrons are constantly in ________ in a region called the ……

motion, electron cloud

a certain number of electrons can be found in each _____________ ________ of the electron cloud

energy level

what's the formula to finding the energy number

2(n)^2

the outermost energy level can hold a maximum of….

8 electrons

the number of electrons in the outermost energy level determines the _________ of an atom

property

pure substances that are made up of one kind of atom

elements

elements cannot be broken down into other substances by ________________ or _____________ means

physical, chemical

atoms of the same element but have a different number of neutrons

isotopes

the atoms of the same __________ will have a different _________

element, mass

if the nucleus of an __________ is unstable then its considered __________________ and will break down over time

isotope, radioactive

the sum of the protons and neutrons is the

mass number

substances that are formed when atoms are combined from certain elements in a certain ratio

compounds

the atoms and the __________ that form compounds can be shown in a chemical formula

ratios

H20 means that there are

2 hydrogen atoms for every oxygen atom

involved the making and breaking of chemical bonds

chemical reactions

when outer electrons are attached, shared, or transferred from one atom to another atom

chemical bond

atoms combine to become

chemically stable

the electrons that are available for atoms to form bonds are called

valence electrons

are formed when one or more electrons are transferred to another atom

ionic bonds

one atom will receive electrons, and that atom will have an overall _______ charge. (usually metals)

positive

atoms with a charge (formed by ionic bonds)

ions

the attraction between the oppositely charged ions hold the compound

together

are formed when atoms share electrons

covalent bonds

single covalent bonds occur when atoms share

2 electrons

double covalent bonds occur when atoms share

4 electrons

triple covalent bonds occur when atoms share

6 electrons

are compounds formed by covalent bonds

molecules

molecules are usually formed between 2 …

nonmetals

the ability of water molecules to attract to one another (cohesion)

high surface tension

which means it moves up small tubes (adhesion)

capillary action

takes a lot of energy for water to evaporate

vaporization

has a high resistance to

temperature change

water _______ when it freezes

expands

occurs when there is an unequal sharing of electrons

polarity

the bonds between the hydrogen atoms of one water molecule with the oxygen atom of a different water molecule

hydrogen bonds

the attraction between molecules of the same substance. (beads of water forms larger beads of water when they combine)

cohesion

the attraction between molecules of different substances. (beads of water on a window)

adhesion

the system used to measure the H+ ions in a solution

pH scale

ranges from being 0-14 with 7 being ________ (water is neutral)

neutral

below 7 means the solution contains more H+ ions than OH- ions. these solutions are…..

acidic

above 7 means the solution contains more H+ ions than OH- ions. These solutions are basic or…

alkaline

are formed when H+ ions are released in the solution (water)

acids

are formed when OH- ions are released in a solution (water)

bases

are weak acids or bases that can react with strong acids or bases to prevent drastic change in pH

buffers