Chemistry - Unit 2 (Read Description)

These do not have everything because some of the things can't be put into flashcard format so I recommend still going through the slides on canvas under modules.

Atoms

Atoms

building blocks of matter

subatomic particles

Protons (+1), electrons (-1), neutrons

Proton

+1 charge, large, found in nucleus

Neutron

No/neutral charge, large, found in nucleus

Electron

-1 charge, very small, found outside of nucleus in electron cloud/orbital

Nucleus

holds protons and neutrons

elements

composed of many atoms of the same kind

Atomic Number

Indicates the number of protons in an atom, which is what defines the element of the atom. The periodic table is arranged in order of increasing the number of protons.

Atomic Mass

Average mass of all of the isotopes of an element. Measured in amu (always remember your units!)

Mass number

the # of protons + # of neutrons which is the atomic mass rounded to a whole number. (changes if # of neutrons changes)

Ions

An atom of molecule with a charge either positive or negative. When the number of protons does NOT equal the number of electrons

Cation

A positively charged atom (less electrons than protons)

Anion

A negatively charged atom (more electrons than protons)

Isotope

Atoms of the same element with different numbers of neutrons (This changes the mass number. Same element, but may have different properties)

The Periodic Table

a chart that organizes elements according to their atomic number and their chemical and physical properties

Groups

a column on the periodic table (there are 18 on the periodic table)

Period

a row on the periodic table (there are 7 on the periodic table)

Metalloids

All are solids at room temp and in between a metal and non-metals. Found directly to either side of the staircase.

metals

solid at room temperature except for mercury, which is a liquid

Non-metals

Most are gases at room temp, except for bromine which is a liquid, and 5 are solids (carbon, phosphorus, sulfur, selenium, iodine)

Chemical Families

a group (column) that contains elements with similar properties because each group has the same number of valence electrons

Transition metals

MOST are hard, strong, and lustrous with high melting points & conduct heat/electricity

Halogens

very reactive nonmetals, combined in nature with other elements

Noble gases

non-reactive gases

Lanthanides: Elements 57-71

Shiny, silvery, soft metals (rare earth metals)

Actinides: Elements 89-103

radioactive metals (many are extremely toxic)

molecule

formed when two or more atoms are joined together chemically (ex: O₂,  H₂0)

compound

formed when two atoms of two or more different elements join together chemically (ex: H₂0,  C₆H₁₂O₆ )

Chemical bond

The force of attraction that holds two or more atoms together (due to the attraction between the positive nucleus & negative electrons)

Valence Electrons

the electrons in the outer shell/orbital that bond with other atoms and have the highest energy

Octet Rule

Atoms try to get 8 valence electrons so they can become stable by gaining, losing, or sharing electrons

Core electrons

under the valence electrons; they are closer to the nucleus

inert

does not react with other atoms

Ionic Bonds

result of the attraction between ions when a metal gives their valence electrons to non-metal (intramolecular)

Covalent Bonds

when an atom shares one or more pairs of electrons with another atom & forms a bond and is common between two nonmetals (weaker and most common chemical bond in living organisms) (intramolecular)

Polar covalent bond

electrons are unequally shared between two atoms which causes one atom to be slightly negative, and one to be slightly positive

Nonpolar covalent bonds

electrons are equally shared between two atoms so the atoms remain neutral in charge

Electronegativity

the tendency of an atom to attract electrons towards itself

hydrogen bonds

An Intermolecular force and these bonds are weak compared to covalent & ionic bonds (It bonds water molecules together)

Intermolecular force

bonds between molecules

intramolecular force

forces between atoms

Metallic bonds

A force that holds atoms together in a metallic substance (Metal + Metal) and are solids made up of tightly packed atoms as a result, valence electrons move freely from one atom to another and they share an electron cloud (intramolecular)