| Term | Definition |
| Nucleus contains | protons and neutrons, + charge, heavy, small, and dense |
| cloud is... | much larger than a nucleus |
| orbitals | varies on the shape of an electron |
| prtotons | +1 charge, heavy mass, located on nucleus |
| Neutron | 0 charge, heavy mass, located in the nucleus |
| Electron | -1 charge, light and located on the electron cloud |
| Atomic number | # of protons, identifies which element an atom is |
| Mass number | # of protons and neutrons |
| Isotopes | same # of protons different number of neutrons |
| Periodic Table | Developed by Dmitri Mendeleev in 1869
Originally ordered by mass
today ordered by atomic number
ordered left to right by increasing atomic # |
| Atomic mass | Not the same as a mass number
average mass of one atom of the element |
| protons | same as atomic number |
| neutrons | maass#-protons |
| electrons | same as atomic number |
| metal | Thermal/electricity (allows heat and electricity to travel through
Malleable,ductile
high density
lustrous(shiny) |
| Semimetal | A.K.A metalloids
properties of both nonmetals and metals
often are semi conductors |
| Organization | periods horizontal rows (left and right)
groups vertical (up and down) |
| group 1 | Alkali metals |
| group 2 | Alkalin earth metals |
| group 3-12 | transition metals |
| group 16 | chalcogens |
| group 17 | halogens |
| group 18 | nobel gases |
| valence electrons | electrons in the outer most shell
atoms can have up to 8 valence electrons
based on group of the periodic table |
| octet rule | atoms want to have 8 valence electrons
atoms can gain, lose, or share valence electrons |
| Atomic radius | The size of an atom as determined by the size of it electron cloud
increase in size from top to bottom
decrease in size from left to tight |
| Ionic Radius | Cations-+ ions (smaller)
Anions- -ions (larger) |
| Ionization energy | atoms ability to attract electrons in a chemical bond
decreases from top to bottom
increases from left to right |
