basic chemistry

atom

atom

Basic unit of matter and smallest part of an element

3 sub-atomic particles

protons, neutrons, electrons

proton (+)

A subatomic particle that has a positive charge and that is found in the nucleus of an atom

neutron (neutral)

A subatomic particle that has no charge and that is found in the nucleus of an atom

electron (-)

A subatomic particle that has a negative charge and found orbiting the nucleus

matter

anything that occupies space and has mass

mass

the quantity of matter an object has

weight

the force produced by gravity acting on the mass of an object

aren't

mass and weight ____ the same

density

the mass of an object divided by its volume

constant

molecules of matter are in ____ motion

states of matter

solid, liquid, gas

solid

fixed volume and shape

liquid

fixed volume, no fixed shape

gas

A state of matter with no definite shape or volume

John dalton

a British chemist who helped develop atomic theory

the big 4

oxygen, carbon, hydrogen, nitrogen

isotope

Atoms of the same element that have extra neutrons

atomic mass number

because of extra neutrons, isotopes are known by their _____

fredrick Soddy

Discovered isotopes

radioactive isotopes

have an unstable nucleus that "breaks down" at a constant rate

radioactivity

What do radioactive isotopes release when they decay?

radiocarbon dating

using them to date specimen (finding how old things are)

radiation therapy

using them to kill cancer

radioactive markers

using them to "tag" molecules

ions

Charged atoms (can be positive or negative)

loses

positive charge is when an atom ___ an electron

gains

negative charge is when an atom ___ an electron

cation

positively charged

anion

negatively charged

chemical

atoms in compounds are held together by ____ bonds

covalent bonds

when two atoms share their electrons to satisfy its valence requirements

water, carbon dioxide, and nitrogen gas

example of a compound bond

ionic bonds

formed because of an attraction between oppositely charged atoms

salt and calcium chloride

examples of ionic bonds

polarity

when electrons (charges) are unevenly distributed across a molecule

dissolve

hydrogen bonds from polarity allow for water's ability to ____ compounds

water

___ allows for 4 hydrogen bonds to form

hydrogen bonds

special bonds formed by charge attraction due to polarity involving hydrogen atoms on one of the compounds

oxygen, nitrogen, and fluorine

what elements typically form hydrogen bonds?

van der Waals forces

a slight attraction (not a bond) that develops between the oppositely charged regions of nearby molecules

properties of water

polarity, cohesion, adhesion, capillarity, density, excellent solvent, saturation point, acid, and base

cohesion

the attraction of water molecules for other water molecules due to hydrogen bonds

adhesion

attraction of water molecules for different molecules due to hydrogen bonds

capillarity

Attraction that results in a rise of water

Density

water is less dense as a solid (ice) than as liquid water

water is less dense as a solid

Why does ice float?

density of everything (least to greatest)

gas<liquid<solid

density of water (least to greatest)

gas<solid<water

ice sheets insulate the water beneath them

why is density a very important quality for life on Earth?

dense

cold water is more _____ than warm water

solutes; pure

water with ____ is more dense than ___ water

depth (going down)

density increases with ____

thermocline

when water gets super cold at a certain depth of water

decreases

water temperature ____ as depth decreases

depth

density increases with ____

increases

as density increases, concentration of solute _____

aqueous solution

a solution in which water is the solvent

solutions

mixture of water and another substance in which the solute is completely dispersed by water

solute

the compound that is dissolved

solvent

the compound that dissolves the solute by hydrogen bonds (it does not have to be water

Saturation Point

the concentration at which no more solute will be dissolved in the solution

hydrogen ion (H+) and hydroxide ion (OH-)

a water molecule is, at any moment, either in the form of H2O or a ___ and ____

pH scale

measurement system for the "potential of hydrogen" (number of hydrogen ions) in solution

0, 14

the pH scale goes from __ to __

extremely acidic

0 on the pH scale is _____ _____

high number of hydrogen ions

very acidic

extremely basic

14 on the pH scale is ____ ___

low number of hydrogen ions

very basic

logarithmic scale

A method of displaying data in multiples of 10

pH 4 has 10x more hydrogen ions than pH 5

example of logarithmic scale

acid

a substance that increases the number of hydrogen ions in a solution (compared to hydroxide ions)

Hydrochloride acid (HCl)

an example of an acid

acidic solution

an ___ ___ has more hydrogen ions in a solution than hydroxide ions

base

a substance that decreases the number of hydrogen ions in a solution

Sodium Hydroxide (NaOH)

an example of a base

basic solution

a , or "alkaline", has less hydrogen ions in a solution than hydroxide

buffer

weak acids and bases that reacts with strong acids or bases to prevent drastic changes in pH