University:
High School
Course:
High School Chemistry
Academic year:

2020
Views:

492

Pages:

3
Author:

Derrick Maldonado

Nucleons - Particles in the nucleus of an atom * Protons * Neutrons Atomic Number - Number of protons in the nucleus of an atom * Identifies the atom * Neutral atom: # of protons (+) = # of electrons Isotope: Atoms of an element that have different numbers of neutrons Isotopes of Hydrogen 1 Hydrogen-1: One proton and No neutrons ¹H p=1 n=0 Hydrogen-2: One proton and One neutron ²H p=1 n=1 Hydrogen-3: One proton and Two neutrons ³H p=1 n=2 Mass Number: Total number of protons and neutrons in an atom Example: Carbon-14 ¹⁴C Neon-20 ²⁰Ne Particle Charge Mass Location Proton +1 1 amu Nucleus Neutron 0 1 amu Nucleus Electron -1 1/1836 amu Orbital = Electron Cloud Atomic Mass: Average of the masses of all the element's isotopes (90 x Mass) + (10 x Mass) / 100 Worksheet: Atomic Structure Name: ___________________________ Use your notes from the Atomic Structure program to answer the following questions. The atomic number tells the number of positively charged Protons in the nucleus of an atom. The atom is Neutral because this is also the number of negatively charged electrons in the atom. The mass number tells the total number of Protons and Neutrons in the nucleus of an atom. These particles collectively are called Nucleons since both are located in the nucleus. Isotopes are atoms of the same element with different numbers of Neutrons which results in different Mass numbers. Write the hyphen notation of the three isotopes of hydrogen: a. Hydrogen-1 ¹H b. Hydrogen-2 ²H c. Hydrogen-3 ³H Fill in the following chart: (Hint: Isotopes may have different masses than the periodic table lists!) Symbol Atomic # Mass # # of protons # of electrons # of neutrons Hg 80 201 80 80 121 Mo 42 96 42 42 54 Cu 29 64 29 29 35 C 6 14 6 6 8 P 15 31 15 15 16 Pb 82 208 82 82 126 Na 11 24 11 11 13 Worksheet: Isotope Problems A student looked up the naturally occurring isotopes of bromine and found the following information: 50.54% of the naturally occurring isotopes of bromine have an atomic mass of 78.92 u while 49.46% of the naturally occurring isotopes of bromine have an atomic mass of 80.92 u. Calculate the average atomic mass of bromine, showing all work: (50.54% x 78.92) + (49.46% x 80.92) = 79.9092 amu Using the following data, calculate the average atomic mass of magnesium (give your answer to the nearest .01 u). Show all work! | Isotope: | Mass | Percent Abundance: | |---|---|---| | Mg-24 | 24 | 78.70% | | Mg-25 | 25 | 10.13% | | Mg-26 | 26 | 11.17% | (0.7870 x 24) + (0.1013 x 25) + (0.1117 x 26) = 24.3247 amu Using the periodic table, What is the average atomic mass of bromine? 79.904 What is the average atomic mass of magnesium? 24.305 How do your calculated answers in #1 and #2 compare to those on the periodic table? Very close