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Home Q & A Board Science-Related Homework Help Chemistry (Moderator: Laser_3)
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obb obb
wrote...
11 years ago
I have a chemistry assignment and i need to find out how many protons, neutrons and electrons there are in N-14, O-16, Cl-35, Ca-40, Mg-24, Co-60, and find the atomic mass and number of elements with 125 protons and 118 neutrons, 122 electrons and 120 neutrons, and 127 protons and 126 neutrons. please help! thanks!
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wrote...
#1
11 years ago
Protons are equal to their atomic numbers
Electrons = Protons
Neutrons = Mass - Protons
iliketorifk Author
wrote...
#2
11 years ago
The atomic number tells you how many protons are in an element. You have the same number of electrons. The difference between the amu and the atomic number equals the number of neutrons.
N-14, atomic number 7, so 7 protons, 7 electrons, 7 neutrons (7 protons + 7 neutrons = 14)
Cl-35, atomic number 17, so 17 protons, 17 electrons, and 18 neutrons (17 protons + 18 neutrons = 35)
wrote...
#3
11 years ago
The number of the element in the Periodic Table shows number of protons. #p+=#e-.
Atomic number=number of  protons( therefore, shows also number of electons in neutral atom). Atomic mass=#p+(number of protpns)+#n(number of neutrons).
N has 7p+,7e-,7n(14-7=7)
O      8p+,8e-,8n(16-8=8)
Cl       17p+,17e-,18n(35-17=18)
Ca      20p,20e,20n
Mg     12p,12e,12n
Co       27p,27e,33n

125p+ means that this is the element #125.
Atomic mass= #p  +#n
125+118=243
122+120=242(because #p=#e)
127+126=253
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