chemistry - chapter 2

pure substances

a substance that is only made out of one type of atom/molecule, and has one set of properties. Ex. water is only made up of H2O molecules.

atoms (smallest particle of any element)

smallest particle of any element that retains the properties of that element. Ex. Fe, Na, Hg

subatomic particles

protons, neutrons, electrons

molecule

a group of two or more atoms bonded together. Ex. CH4

Diatomic elements

7 elements that never exist on their own but are always bonded with another atom of itself. They area all molecules

element

a pure substance that is only made up of one type of particles. Ex Au

compound

a pure substance that is made up of 2 or more types of particles bonded together. Ex. O6

protons

positively charged, found in nucleus, and similar size as neutrons.

atomic number

number of protons

electrons

negatively charges, found in energy shells around the nucleus, and are much smaller and lighter than protons and neutrons

neutrons

no charge, found in nucleus, and similar size as proton,

semi-metals/metalloids

share metal and non-metal properties

Dmitri Mendeleez

organizer of the periodic table

Alkali Metals

highly reactive (explosive with water), soft, shiny/sliver, and has an ion charge of +1

alkaline earth metal

somewhat reactive (react with water but not explosively, soft, shiny and silvery white, has a ion charge of +2

transition metals

less reactive, hard/tough, has a high melting point and density

halogens

highly reactive, don’t have consistent state, has a low boiling point, poisonus, has a ion charge of -1

noble gases

non-reactive, don’t form compounds, are gases, has an ion charge of 0

Covalent

two or more non-metals bonded together

ionic

a metal and a non-metal bonded together

atomic number

amount of protons and electrons in an element

mass - atomic number

amount of neutrons in an element

electron = atomic # - ion charge

calculate the number of electrons (ion)

first shell: 2 electrons second shell: 8 electrons third shell: 8 electrons

bohr diagram rules

valence shells

outermost shell

full valence shell

atoms are stable

chemical reactivity

the closer they are to a full shell, the more reactive they will be

ion charge is -

gets extra electrons

ion charge is +

gives away electrons