Define the following terms. 1. proton 2. neutron 3. electron 4. nucleus
proton: ▪ a subatomic particle that is found in the nucleus of an atom ▪ it has a positive charge and a mass of 1 amu neutron: ▪ a subatomic particle that is found in the nucleus of an atom ▪ it has no charge and a mass of 1 amu
electron: ▪ a subatomic particle that is found outside the nucleus in energy levels ▪ it’s constantly moving ▪ it has a negative charge and no mass nucleus: ► the center of an atom ► contains protons and neutrons ► contains the mass of the atom ► very, very small and dense
Why is it appropriate to say that atoms are the “building blocks” of all matter?
Many periodic tables look different but still contain similar information.
1. atomic number - tells the # of protons (p + ) the atom has, by definition - also tells the # electrons (e - ), b/c atoms are neutral 2. chemical symbol - letter(s) that represent specific elements – only contain one capital letter 3. atomic mass - number of protons + the number of neutrons in one atom of the element (an average) - almost all mass is found in the nucleus of the atom