Download ATOMIC INFORMATION

Survey
yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Document related concepts
no text concepts found
Transcript
ATOMIC INFORMATION
A. Periodic Boxes
Three pieces of information are identified in each box:
Atomic number
Atomic symbol
13
Al
26.9815
Average atomic mass
B. Atomic Number- the number of protons in the nucleus of an atom
1. An element consists of atoms that have the same number of protons, therefore the same
atomic number.
Ex. C = 6, Sn = 50, Au = 79
2. isotopes- atoms of the same element that have different atomic masses
a. their nuclei have a different number of neutrons
b. there is no difference in chemical properties
c. nuclide- each variety of an atom based on mass when compared to another atom
Ex. hydrogen-1, hydrogen-2, hydrogen-3
carbon-12, carbon-14
C. Mass
1. average atomic mass- the result of average the presence of all isotopic forms of an element
2. amu (atomic mass units)- based on the carbon-12 = 12 scale, arbitrary assignment of value
3. mass number- the whole number obtained from rounding the average atomic mass; used for
counting particles; a proton = 1, a neutron = 1, an electron = 0.
D. Calculating Average Atomic Mass
If lithium-6 = 6.015 amu at 7.42% abundance and lithium-7 = 7.016 amu at 92.58%, what is the
average atomic mass?
6.015(.0742) + 7.016(.9258) = 6.941 amu for lithium atoms
Practice:
The average atomic mass of boron is 10.81 amu. If the smaller abundance is boron-10 at 10.013
amu and the other isotope is boron-11 at 11.009, what are the percentages of each?
E. Subatomic Particles
1. For atoms, # protons = # electrons
2. Atomic number = # protons = # electrons
3. Mass number = # protons + # neutrons, so # neutrons = mass number - # protons
Practice:
Identify the # protons, # electrons, mass number, and # neutrons for the following elements:
silicon
barium
chlorine-37
Related documents