Gathering Atomic Information ALMOST ALL OF THE INFORMATION

Gathering Atomic Information ALMOST ALL OF THE INFORMATION YOU NEED TO KNOW ABOUT A PARTICULAR ELEMENT CAN BE FOUND BY LOOKING AT THE PERIODIC TABLE WILL TYPICALLY HAVE ONE OF THE FOLLOWING FORMATS:

If this stadium were the size of an atom’s electron cloud, the nucleus would be the size of a marble setting on the 50 yard line. Electrons occupy the VOLUME, protons and neutrons constitute the MASS of an atom.

Subatomic Particles � Protons and electrons are the only particles that have a charge. � Protons and neutrons have essentially the same mass. � The mass of an electron is so small (2000 time smaller than the proton), we ignore it. 0. 0005486 is the way to write this number! 3

What do all atoms of the same element have in common? ***Atoms of the same element always contain the same number of protons!***

What is the name of the two numbers on an element’s square of the periodic table? Carbon 12. 011 C 6 �Atomic Number: Smallest of the two numbers Always a whole number Indicates number of protons 6 C Carbon 12. 011 �Average Mass Average number of protons (p+) and neutrons Usually a decimal �Mass Number Go to the PT # of protons and neutrons added together round the average atomic weight to the nearest whole number to find the most common combination of p+ and n (isotope)

What information can be obtained from the two numbers on a square of the periodic table? Subatomic Particle & symbol Charge Mass (amu) Location (region) How to find number in an atom Founder and Date Proton (p+) Positive (+) 1 Nucleus Same as atomic number E. Rutherford 1914 Neutron (n) or (0) Neutral 1 Nucleus Mass # -Atomic # # Neutrons J Chadwick 1932 Electron (e-) Negative (-) 0 Electron cloud Same as JJ Thomson atomic 1897 number in a neutral atom

How are the particles related? Atoms Electron Cloud Nucleus Region Subatomic Particle Charge Balance Neutron 0 Proton + electron -

Isotope ATOMS OF THE SAME ELEMENT THAT HAVE DIFFERENT NUMBER OF NEUTRONS

Models of Carbon Isotopes Carbon-12 6 p+ 6 n Carbon-13 6 p+ 7 n Carbon-14 6 p+ 8 n �How are isotopes of the same element identified? Isotopes are identified by the name of the element and by the atom’s mass number (written like Li-6 or Li-7) It’s called ISOTOPE NOTATION

Lithium Isotope Examples Isotope Name Symbol # protons # neutrons # electrons Lithium-6 Li-6 3 3 3 Lithium-7 Li-7 3 4 3 Chlorine-35 Cl-35 17 18 17 Chlorine-37 Cl-37 17 20 17

How to find Mass Number �Number of protons AND neutrons (added together) of a specific isotope of an element. �Mass Number = #p + #n �Found one of two ways (prioritized) Given to you after the element symbol (isotope notation) � C-14 or Na-23 � 100% accuracy Most common isotope method (mci). Round the average atomic mass value from the periodic table to the nearest whole number � Carbon’s Atomic mass is 12. 011 = round to 12 � Manganese’s Atomic mass is 54. 95 = round to 55 � 50% accuracy