Negatively charged subatomic particle that orbits the nucleus of an atom
Proton
Positively charged subatomic particle that is located in the nucleus of an atom.
Neutrons
Uncharged subatomic particles that hold protons and electrons together. (protons repell other protons..)
Atomic number
Number of protons in the nucleus (number at top of element square in periodic table.)
Z
Number of protons
A
A= mass number = number of nucleons = # of protons +neutrons.
finding z and a
Example:
Flourine 9p
9e
10n
Z=9 A= 19
Valence electrons
These are the outer most electrons. they are the most chemically important. this number is the small number for the groups on the periodic table (1- 8)
Neutrons
can be found by subtracting bottom number from top number in periodic table.
Noble gas atoms
They are stable and will not react with other atoms. They all have 8 valence electrons except for helium which has 2.
Unit
There are no joined molecules. Metal paired with non metal is a good indicator. Example
NaCl Na+Cl
Octet / noble gas rule
Unstable atoms react to reach a stable state that has the same number of electrons as the nearest (by atomic number in periodic table) noble gas... valence electrons can be transferred
ionic bond
Results from transfer of electrons between metals (cation) and non metals (anion)
Covalent bonds
sharing of electrons between non metals
General properties of ionic compounds
Usually found as solid
needs very high temp to become l or g
many dissolve in water
Polyatomic ions
a charged species (ion) composed of two or more atoms covalently bonded or of a metal complex that can be considered to be acting as a single unit in the context of acid and base chemistry or in the formation of salts.