4.2 -3 Structure of the Atom

Location of Particles Nucleus (positive charge) Protons and Neutrons Electron Cloud (negative charge) Electrons video

Nucleus size Nucleus v. electron cloud Do you see the tiny star? *

Atomic Number Mass Number The number of protons in the nucleus Number of protons plus number of neutrons # of Protons: 2 # of Electrons: 2 # of Neutrons: 2

H He 126C 73Li Iron-56 3517Cl Neon-20 3919K 2412Mg Sr-88 As I Ag S Element Atomic # Atomic Mass Mass # Protons Electrons Neutrons H   1  1.0079  1 1 He  2 4.0026  4 2 126C   73Li Iron-56 26 55.847 56 30 3517Cl Neon-20 3919K 2412Mg Sr-88 As I Ag S

Calculating Average Atomic Mass Isotopes The average atomic mass is based on the mass of all the different isotopes of one element. For Example: Hydrogen has three isotopes. Hydrogen-1, Hydrogen-2, and Hydrogen-3

Mass x Abundance (1.00784 x 0.99985) + (2.0141 x 0.00015) + (3.0160 x 0) = 1.0079 Mass x Abundance 15.9949 x 0.9976 + 16.9991 x 0.0004 + 17.9991 x 0.0020 = 15.999

1) Draw a box representing Nitrogen off your periodic table 1) Draw a box representing Nitrogen off your periodic table. Label : 1) mass number/Atomic mass, 2)Atomic number, 3) symbol, 4) name. 2)Write an isotope for Potassium-42. Label mass number and atomic number. ATOMIC SIZE 3)Where is most of the mass located in atom? 4)What is in the nucleus of the atom? 5) Where is most of the volume of the atom? 6) What is the atom mostly made up of? 7) If the atom were enlarged until the nucleus was the size of the eraser on a pencil, how big would the rest of the atom be?